Fix flaky parallel recompilation test.

On very rare circumstances parallel recompilation would install
the optimized method earlier than expected and the test would fail.

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/24495005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16933 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Less aggressive polling when concurrently compiling for OSR.

Changes include:
- completed concurrent OSR tasks trigger a stack check interrupt.
- polling for completion is now guarded by a stack check.
- circular buffer for completed OSR tasks instead of list.

R=titzer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/24237009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16934 ce2b1a6d-e550-0410-aec6-3dcde31c8c00