[pkg/test_runner] Only use .dll for assembled snapshots on Windows.

Use "out.aotsnapshot" as the name for all non-assembled snapshots and
names with the appropriate shared object extension for the host OS for
assembled snapshots.

This ensures the test checks for .dll extensions added in
https://dart-review.googlesource.com/c/sdk/+/428200 only trigger
for assembled snapshots as expected, and not for other formats
(e.g., Windows trybots using sanitizers, which still use direct
to ELF snapshots).

Also fixes incorrect line numbers in dwarf_stack_trace_test.dart.

TEST=vm/dart/build_id_test
     standalone/dwarf_stack_trace_test

Cq-Include-Trybots: luci.dart.try:vm-asan-win-release-x64-try,vm-linux-release-x64-try,vm-mac-release-arm64-try
Bug: #60846
Change-Id: Ife06613d86874d76adeb99dcbc50fc3723aae584
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/432660
Reviewed-by: Ryan Macnak <[email protected]>
Commit-Queue: Tess Strickland <[email protected]>

Author: sstrickl

pkg/test_runner/lib/src/compiler_configuration.dart

@@ -1409,15 +1409,17 @@ abstract mixin class VMKernelCompilerMixin {
   String tempAssemblyFile(String tempDir) =>
       Path('$tempDir/out.S').toNativePath();
   String tempAOTFile(String tempDir) {
-    switch (_configuration.system) {
-      case System.android:
-      case System.fuchsia:
-      case System.linux:
-        return Path('$tempDir/libout.so').toNativePath();
-      case System.mac:
-        return Path('$tempDir/libout.dylib').toNativePath();
-      case System.win:
-        return Path('$tempDir/out.dll').toNativePath();
+    if (_configuration.genSnapshotFormat == GenSnapshotFormat.assembly) {
+      switch (_configuration.system) {
+        case System.android:
+        case System.fuchsia:
+        case System.linux:
+          return Path('$tempDir/libout.so').toNativePath();
+        case System.mac:
+          return Path('$tempDir/libout.dylib').toNativePath();
+        case System.win:
+          return Path('$tempDir/out.dll').toNativePath();
+      }
     }
     return Path('$tempDir/out.aotsnapshot').toNativePath();
   }

tests/standalone/dwarf_stack_trace_test.dart

@@ -211,14 +211,14 @@ final expectedCallsInfo = <List<DartCallInfo>>[
     DartCallInfo(
       function: "bar",
       filename: "dwarf_stack_trace_test.dart",
-      line: 17,
+      line: 18,
       column: 3,
       inlined: true,
     ),
     DartCallInfo(
       function: "foo",
       filename: "dwarf_stack_trace_test.dart",
-      line: 23,
+      line: 24,
       column: 3,
       inlined: false,
     ),
@@ -228,7 +228,7 @@ final expectedCallsInfo = <List<DartCallInfo>>[
     DartCallInfo(
       function: "main",
       filename: "dwarf_stack_trace_test.dart",
-      line: 29,
+      line: 30,
       column: 5,
       inlined: false,
     ),