Language tests updated to use const instead of final.

tests/language/string_interpolation1_negative_test.dart

Index: tests/language/string_interpolation1_negative_test.dart
diff --git a/tests/language/string_interpolation1_negative_test.dart b/tests/language/string_interpolation1_negative_test.dart
index fe6f8c920687ca6b78ff81f05cff08e4a2556d8a..15ccfe422918a873b2468c6c39b66dd2e77ba552 100644
--- a/tests/language/string_interpolation1_negative_test.dart
+++ b/tests/language/string_interpolation1_negative_test.dart
@@ -11,7 +11,7 @@ class A {
 
 class StringInterpolation1NegativeTest {
   // Dollar not followed by "{" or identifier.
-  static final DOLLAR = const A("$");
+  static const DOLLAR = const A("$");
   testMain() {
   }
 }