Remove clear_safari_cache flag in tools/test.py

tools/testing/dart/test_options.dart

Index: tools/testing/dart/test_options.dart
diff --git a/tools/testing/dart/test_options.dart b/tools/testing/dart/test_options.dart
index a33224abde67544302e75290d6c55f058809bb28..994e786f7e83595f2fef78bc0305193767b419b8 100644
--- a/tools/testing/dart/test_options.dart
+++ b/tools/testing/dart/test_options.dart
@@ -348,13 +348,6 @@ Note: currently only implemented for dart2js.''',
               false,
               type: 'bool'),
           new _TestOptionSpecification(
-              'clear_safari_cache',
-              'Clear the safari cache (i.e., delete it).',
-              ['--clear_safari_cache'],
-              [],
-              false,
-              type: 'bool'),
-          new _TestOptionSpecification(
               'clear_browser_cache',
               'Browser specific clearing of caches(i.e., delete it).',
               ['--clear_browser_cache'],
@@ -724,12 +717,6 @@ Note: currently only implemented for dart2js.''',
     // Allow suppression that is valid for all ie versions
     configuration['ie'] = runtime.startsWith('ie');
 
-    // Temporary grace period for clear_safaci_cache
-    // See issue 18478
-    if (configuration['clear_safari_cache']) {
-      configuration['clear_browser_cache'] = true;
-    }
-
     // Expand the test selectors into a suite name and a simple
     // regular expressions to be used on the full path of a test file
     // in that test suite. If no selectors are explicitly given use