[analyzer] Stop generating the diagnostics.md file

dart.dev now consumes the source YAML files, so generating the Markdown file is no longer necessary.

The contents of the YAML files are still verified as before.

Resolves dart-lang/site-www#6387

Change-Id: I8b989b598ec3c7abef66242dceb9d5a481f43e39
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/407640
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Auto-Submit: Parker Lougheed <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>

Author: parlough

pkg/analyzer/test/verify_diagnostics_test.dart

@@ -3,11 +3,9 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/error/error.dart';
-import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
-import '../tool/diagnostics/generate.dart';
 import '../tool/messages/error_code_documentation_info.dart';
 import '../tool/messages/error_code_info.dart';
 import 'src/dart/resolution/context_collection_resolution.dart';
@@ -421,25 +419,6 @@ class VerifyDiagnosticsTest {
     //
     DocumentationValidator validator = DocumentationValidator();
     await validator.validate();
-    //
-    // Validate that the generator has been run.
-    //
-    String actualContent = PhysicalResourceProvider.INSTANCE
-        .getFile(computeOutputPath())
-        .readAsStringSync();
-    // Normalize Windows line endings to Unix line endings so that the
-    // comparison doesn't fail on Windows.
-    actualContent = actualContent.replaceAll('\r\n', '\n');
-
-    StringBuffer sink = StringBuffer();
-    DocumentationGenerator generator = DocumentationGenerator();
-    generator.writeDocumentation(sink);
-    String expectedContent = sink.toString();
-
-    if (actualContent != expectedContent) {
-      fail('The diagnostic documentation needs to be regenerated.\n'
-          'Please run tool/diagnostics/generate.dart.');
-    }
   }
 
   test_published() {