It only has one call size ({CompileToModuleObject}), which just tail
calls into {CompileToModuleObjectInternal}. Thus, merge the two.

R=titzer@chromium.org

Bug: v8:7754
Change-Id: I6344f257279f049fd6cab51114988f7e1c019272
Reviewed-on: https://chromium-review.googlesource.com/1104157Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53787}