This fixes the bogus implementation of the function in question and adds
test coverage for the deserialization of the corresponding flags from
the serialized scope info. Note that the tests so far only cover cases
where the module and the function contain context-allocated variables.

R=verwaest@chromium.org
TEST=cctest/test-parsing/AsmFunctionFlag
BUG=v8:5653

Review-Url: https://codereview.chromium.org/2507063004
Cr-Commit-Position: refs/heads/master@{#41093}