Remove System.normalResolve(); use names not urls in Loader.

System.normalResolve() was incorrect, we should be calling normalize() in all cases.
System.locate() should only be called just before fetch().
Fixes #394, Fixes #393

Review URL: https://github.com/google/traceur-compiler/pull/636

Closes #636, closes #394, closes #393.
Revert "wip"

This reverts commit 81f05377583c8a13b03c2449a4faf15e9bc91ce8.
The patch from another incomplete branch got committed with
a correct patch for PR #636
Rename AttachReferrerNameTransformer to AttachModuleNameTransformer.
This should have been in PR #636; I don't know how it was not.
Move .locate() from System to LoaderHooks.

This function is called by the Loader before fetch();
it is essential private API between Loader and LoaderHooks.

Review URL: https://github.com/google/traceur-compiler/pull/638

Closes #638.