Avoid allocating a0 for both the return value and the first param.

       Upstream had fix it.
       Refer to https://bugs.chromium.org/p/v8/issues/detail?id=11063.

  fix #330

Refer to c7cb9bec.

Refer to 146c9708.

Proper naming is required by upstream lint checkers.

It has already been added at the top of the file.

Resolves #300

Fixes #299