Ensure a test of Alert.dismiss actually calls Alert.dismiss
Remove a class of our which replicates HTTP status codes already given meaningful names in the standard JRE.
Bump the hmltunit version to 2.14

This also fixes the buck builds. There are two known build failures in the htmlunit JS
tests, but these failed with the prior release, and so we're functionally equivalent.
Update Closure library to head (5a4878ece3dd35230a21d745411ab0985cf99e15)
Update Closure compiler to v20140407
Revert "Update Closure library to head (5a4878ece3dd35230a21d745411ab0985cf99e15)"

This reverts commit 10d8abebb47447391635d7eb7cab3f8bb5d276e4.

Compiler update requires Java 7, which is not on CI
Library update requires compiler update