allow JS builtin to be typed as needed

test/browser/language_tests.js

Index: test/browser/language_tests.js
diff --git a/test/browser/language_tests.js b/test/browser/language_tests.js
index 2d05cfed8149ff293918b1f9783367f8e9a62fce..1155e0d0fffd8861a64236f46c6daad3dc68bc27 100644
--- a/test/browser/language_tests.js
+++ b/test/browser/language_tests.js
@@ -194,6 +194,7 @@
     'int_test',
     'integer_division_by_zero_test',
     'interceptor_test',
+    'interceptor9_test',

[Jennifer Messerly, 2016/01/28 00:46:18]

The interceptor9_test expects to create a typed array, checks that an "is" check
works, then triggers a no such method on it.

However the catch is not precise enough--it would allow any error other than
ExpectException(!), and made no attempt to verify where the error was thrown.
Previously we were failing on a DDC cast inside typed_data constructor, so we
never even reached the "is" check. Now we make it there, but we fail the `is`
check, causing the test to fail.

It is good the test fails, because typed_data is not implemented correctly yet.
:)

Aside: the test could've been more straightforwardly written, but it goes to
great pains to confuse dart2js, confusing itself in the process. ;)

     'is_nan_test',
     'issue10747_test',
     'issue13179_test',