Remove unused macros, and move macro definitions used only in a single
file into the file itself.

Cq-Include-Trybots: master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: If62107816ad1e6addf58705a075d3eba4f23bf08
Reviewed-on: https://chromium-review.googlesource.com/721381Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48625}