Enable and remove the flag for --incompatible_restrict_attribute_names

RELNOTES: incompatible_restrict_attribute_names is enabled (https://github.com/bazelbuild/bazel/issues/6437)
PiperOrigin-RevId: 263841325
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
index 54ca283..fc9c05f 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
@@ -199,42 +199,16 @@
 
   @Test
   public void testAttrNameSpecialCharactersAreForbidden() throws Exception {
-    ev =
-        createEvaluationTestCase(
-            StarlarkSemantics.DEFAULT_SEMANTICS.toBuilder()
-                .incompatibleRestrictAttributeNames(true)
-                .build());
-    ev.initialize();
-
     ev.setFailFast(false);
     evalAndExport("def impl(ctx): return", "r = rule(impl, attrs = {'ab$c': attr.int()})");
-    ev.assertContainsError("attribute name `ab$c` is not a valid identfier");
+    ev.assertContainsError("attribute name `ab$c` is not a valid identifier");
   }
 
   @Test
   public void testAttrNameCannotStartWithDigit() throws Exception {
-    ev =
-        createEvaluationTestCase(
-            StarlarkSemantics.DEFAULT_SEMANTICS.toBuilder()
-                .incompatibleRestrictAttributeNames(true)
-                .build());
-    ev.initialize();
-
     ev.setFailFast(false);
     evalAndExport("def impl(ctx): return", "r = rule(impl, attrs = {'2_foo': attr.int()})");
-    ev.assertContainsError("attribute name `2_foo` is not a valid identfier");
-  }
-
-  @Test
-  public void testAttrNameSpecialCharactersLegacy() throws Exception {
-    ev =
-        createEvaluationTestCase(
-            StarlarkSemantics.DEFAULT_SEMANTICS.toBuilder()
-                .incompatibleRestrictAttributeNames(false)
-                .build());
-    ev.initialize();
-
-    evalAndExport("def impl(ctx): return", "r = rule(impl, attrs = {'ab$c': attr.int()})");
+    ev.assertContainsError("attribute name `2_foo` is not a valid identifier");
   }
 
   @Test