Ensure code flushing is disabled in incremental marking.
Ensure code flushing is disabled in incremental marking.

This fixes some test failures since r12714 which shared the code for
code flushing between full and incremental marking and is only a quick
fix until we can enable incremental code flushing.

R=jkummerow@chromium.org
BUG=v8:1609

Review URL: https://codereview.chromium.org/11137014

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@12723 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh