[analysis_server] Fix line endings in snippets

This removes `useLineEndingsForPlatform=false` from the Snippets tests and updates them to use a shared method that correctly handles normalization of the `expected` result.

It turned out that we had bugs here, with the correct line endings not being used, so it also fixes that by passing `eol` to the `ChangeBuilder`s created by the snippet producers.

Progress towards #60234

Change-Id: I851fee987dda52f329d110878e10593cbced8c6c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/433780
Reviewed-by: Samuel Rawlins <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: DanTup

pkg/analysis_server/lib/src/services/snippets/dart/class_declaration.dart

@@ -18,7 +18,10 @@ class ClassDeclaration extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
 
     await builder.addDartFileEdit(request.filePath, (builder) {

pkg/analysis_server/lib/src/services/snippets/dart/do_statement.dart

@@ -18,7 +18,10 @@ class DoStatement extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
 
     await builder.addDartFileEdit(request.filePath, (builder) {

pkg/analysis_server/lib/src/services/snippets/dart/flutter_stateful_widget.dart

@@ -28,7 +28,10 @@ class FlutterStatefulWidget extends FlutterSnippetProducer
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
 
     // Checked by isValid().
     var classStatefulWidget = this.classStatefulWidget!;

pkg/analysis_server/lib/src/services/snippets/dart/flutter_stateful_widget_with_animation.dart

@@ -35,7 +35,10 @@ class FlutterStatefulWidgetWithAnimationController
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
 
     // Checked by isValid().
     var classStatefulWidget = this.classStatefulWidget!;

pkg/analysis_server/lib/src/services/snippets/dart/flutter_stateless_widget.dart

@@ -28,7 +28,10 @@ class FlutterStatelessWidget extends FlutterSnippetProducer
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
 
     // Checked by isValid().
     var classStatelessWidget = this.classStatelessWidget!;

pkg/analysis_server/lib/src/services/snippets/dart/for_in_statement.dart

@@ -18,7 +18,10 @@ class ForInStatement extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
     var varOrFinal = codeStyleOptions.makeLocalsFinal ? 'final' : 'var';
 

pkg/analysis_server/lib/src/services/snippets/dart/for_statement.dart

@@ -18,7 +18,10 @@ class ForStatement extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
 
     await builder.addDartFileEdit(request.filePath, (builder) {

pkg/analysis_server/lib/src/services/snippets/dart/function_declaration.dart

@@ -18,7 +18,10 @@ class FunctionDeclaration extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
 
     await builder.addDartFileEdit(request.filePath, (builder) {

pkg/analysis_server/lib/src/services/snippets/dart/if_else_statement.dart

@@ -18,7 +18,10 @@ class IfElseStatement extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
 
     await builder.addDartFileEdit(request.filePath, (builder) {

pkg/analysis_server/lib/src/services/snippets/dart/if_statement.dart

@@ -18,7 +18,10 @@ class IfStatement extends DartSnippetProducer {
 
   @override
   Future<Snippet> compute() async {
-    var builder = ChangeBuilder(session: request.analysisSession);
+    var builder = ChangeBuilder(
+      session: request.analysisSession,
+      eol: utils.endOfLine,
+    );
     var indent = utils.getLinePrefix(request.offset);
 
     await builder.addDartFileEdit(request.filePath, (builder) {