Update pattern test to account for new DDC JS variable naming (#2542)

* Update pattern test to account for new DDC JS variable naming

A bug recently uncovered in DDC required renaming some variables (primarily around patterns) to avoid declarations from shadowing each other incorrectly. 'a' is now 'a$' as it is the second case that declares a Dart variable named 'a'.

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Co-authored-by: Nate Biggs <natebiggs@google.com>

dwds/test/instances/common/patterns_inspection_common.dart

@@ -5,6 +5,7 @@
 import 'package:test/test.dart';
 import 'package:test_common/logging.dart';
 import 'package:test_common/test_sdk_configuration.dart';
+import 'package:test_common/utilities.dart';
 import 'package:vm_service/vm_service.dart';
 
 import '../../fixtures/context.dart';
@@ -96,11 +97,24 @@ void runTests({
       await onBreakPoint('testPatternCase2', (event) async {
         final frame = event.topFrame!;
 
-        expect(await getFrameVariables(frame), {
-          'obj': matchListInstance(type: 'Object'),
-          'a': matchPrimitiveInstance(kind: InstanceKind.kString, value: 'b'),
-          'n': matchPrimitiveInstance(kind: InstanceKind.kDouble, value: 3.14),
-        });
+        if (dartSdkIsAtLeast('3.7.0-246.0.dev')) {
+          expect(await getFrameVariables(frame), {
+            'obj': matchListInstance(type: 'Object'),
+            // Renamed to avoid shadowing variables from previous case.
+            'a\$':
+                matchPrimitiveInstance(kind: InstanceKind.kString, value: 'b'),
+            'n\$':
+                matchPrimitiveInstance(kind: InstanceKind.kDouble, value: 3.14),
+          });
+        } else {
+          expect(await getFrameVariables(frame), {
+            'obj': matchListInstance(type: 'Object'),
+            // Renamed to avoid shadowing variables from previous case.
+            'a': matchPrimitiveInstance(kind: InstanceKind.kString, value: 'b'),
+            'n':
+                matchPrimitiveInstance(kind: InstanceKind.kDouble, value: 3.14),
+          });
+        }
       });
     });