Make RegExp constructor non-const.

tests/corelib/reg_exp4_test.dart

Index: tests/corelib/reg_exp4_test.dart
diff --git a/tests/corelib/reg_exp4_test.dart b/tests/corelib/reg_exp4_test.dart
index 2daca498cf9b5809540db9502a7db5e28428a06d..41d8f50743f884e8d72294849ec0d716d420d9c6 100644
--- a/tests/corelib/reg_exp4_test.dart
+++ b/tests/corelib/reg_exp4_test.dart
@@ -5,7 +5,7 @@
 
 main() {
   try {
-    RegExp ex = const RegExp(null);
+    RegExp ex = new RegExp(null);
     Expect.fail("Expected: NullPointerException got: no exception");
   } on Exception catch (ex) {
     if (!(ex is NullPointerException)) {
@@ -13,7 +13,7 @@ main() {
     }
   }
   try {
-    const RegExp(r"^\w+$").hasMatch(null);
+    new RegExp(r"^\w+$").hasMatch(null);
     Expect.fail("Expected: NullPointerException got: no exception");
   } on Exception catch (ex) {
     if (!(ex is NullPointerException)) {
@@ -21,7 +21,7 @@ main() {
     }
   }
   try {
-    const RegExp(r"^\w+$").firstMatch(null);
+    new RegExp(r"^\w+$").firstMatch(null);
     Expect.fail("Expected: NullPointerException got: no exception");
   } on Exception catch (ex) {
     if (!(ex is NullPointerException)) {
@@ -29,7 +29,7 @@ main() {
     }
   }
   try {
-    const RegExp(r"^\w+$").allMatches(null);
+    new RegExp(r"^\w+$").allMatches(null);
     Expect.fail("Expected: NullPointerException got: no exception");
   } on Exception catch (ex) {
     if (!(ex is NullPointerException)) {
@@ -37,7 +37,7 @@ main() {
     }
   }
   try {
-    const RegExp(r"^\w+$").stringMatch(null);
+    new RegExp(r"^\w+$").stringMatch(null);
     Expect.fail("Expected: NullPointerException got: no exception");
   } on Exception catch (ex) {
     if (!(ex is NullPointerException)) {