[analysis_server] Remove useLineEndingsForPlatform

Nobody sets this variable anymore. Any tests going through shared helpers that use `normalizeSource()` are always normalized now.

Change-Id: Idfe3b6430453ad2f92bee950b7a0d60c4a74d135
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/444281
Commit-Queue: Brian Wilkerson <[email protected]>
Reviewed-by: Samuel Rawlins <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>

Author: DanTup

pkg/analysis_server/test/abstract_context.dart

@@ -33,9 +33,6 @@ class AbstractContextTest
 
   static final ByteStore _byteStore = MemoryByteStore();
 
-  /// Whether to rewrite line endings in test code based on platform.
-  bool useLineEndingsForPlatform = true;
-
   final Map<String, String> _declaredVariables = {};
   AnalysisContextCollectionImpl? _analysisContextCollection;
 
@@ -203,9 +200,8 @@ class AbstractContextTest
   }
 
   /// Convenience function to normalize newlines in [code] for the current
-  /// platform if [useLineEndingsForPlatform] is `true`.
-  String normalizeSource(String code) =>
-      useLineEndingsForPlatform ? normalizeNewlinesForPlatform(code) : code;
+  /// platform.
+  String normalizeSource(String code) => normalizeNewlinesForPlatform(code);
 
   Future<AnalysisSession> sessionFor(File file) async {
     var analysisContext = _contextFor(file);

pkg/analyzer/lib/src/test_utilities/platform.dart

@@ -12,15 +12,16 @@ String get testEol =>
     //  existing `TEST_ANALYZER_WINDOWS_PATHS` var) to allow testing
     //  `\n` on Windows or `\r\n` on non-Windows, to ensure we don't have any
     //  code just assuming the platform EOL (instead of the files EOL).
+    //  [normalizeNewlinesForPlatform] may need updating to not assume it only
+    //  needs to run for Windows.
     Platform.lineTerminator;
 
 /// Normalizes content to use platform-specific newlines.
 ///
 /// This ensures that when running on Windows, '\r\n' is used, even though
 /// source files are checked out using '\n'.
 String normalizeNewlinesForPlatform(String input) {
-  // TODO(dantup): Once all instances of useLineEndingsForPlatform have been
-  //  removed, we should try to minimize the number of explicit calls here from
+  // TODO(dantup): Try to minimize the number of explicit calls here from
   //  tests and have them automatically normalized.
 
   // Skip normalising for other platforms, as the 'gitattributes' for the Dart