Handle escapes in string literals.

frog/tests/leg/src/BuiltinInterceptorTest.dart

Index: frog/tests/leg/src/BuiltinInterceptorTest.dart
diff --git a/frog/tests/leg/src/BuiltinInterceptorTest.dart b/frog/tests/leg/src/BuiltinInterceptorTest.dart
index 05061e534e10cfbecba744c741e6b2a47d72df37..092c81313b9e0337f1228eb44ba63df4c12993cd 100644
--- a/frog/tests/leg/src/BuiltinInterceptorTest.dart
+++ b/frog/tests/leg/src/BuiltinInterceptorTest.dart
@@ -26,17 +26,16 @@ main() {
   String generated = compile(TEST_ONE, 'foo');
   Expect.isTrue(generated.contains("return a.length;"));
 
-  // TODO(ngeoffray): Enable once we support raw strings
-  // and folding of length.
-  Exception exception;
+  // TODO(lrn): Reenable when we start constant folding string length properly.
+  bool failed = false;
   try {
     generated = compile(TEST_TWO, 'foo');
     Expect.isTrue(generated.contains("return 3;"));
 
     generated = compile(TEST_THREE, 'foo');
     Expect.isTrue(generated.contains("return 3;"));
-  } catch (var e) {
-    exception = e;
+  } catch (Exception e) {
+    failed = true;
   }
-  Expect.isTrue(exception != null);
+  Expect.isTrue(failed);
 }