Allow running mjsunit/manual-parallel-recompile on single-core systems.

Allow running mjsunit/manual-parallel-recompile on single-core systems.

- Add an %IsParallelSupported() builtin function to  make possible to check support of parallel processing from JavaScripts.
- Change the test script that if parallel recompilation is forced on a single core CPU, expect that it won't be recompiled in parallel.
- Change the  JSFunction::MarkForParallelRecompilation() to fall back gracefully if parallel recompilation is not supported.

BUG=v8:2733
TEST=mjsunit/manual-parallel-recompile

[Yang, 2013-06-17 14:07:58]

LGTM. Thanks for fixing this!

https://codereview.chromium.org/17277002/diff/1/src/runtime.h
File src/runtime.h (right):

https://codereview.chromium.org/17277002/diff/1/src/runtime.h#newcode98
src/runtime.h:98: F(IsParallelSupported, 0, 1) \
Maybe rename to indicate that it's compilation-related. We also got parallel
sweeping etc.

[kilvadyb, 2013-06-17 16:02:36]

https://codereview.chromium.org/17277002/diff/1/src/runtime.h
File src/runtime.h (right):

https://codereview.chromium.org/17277002/diff/1/src/runtime.h#newcode98
src/runtime.h:98: F(IsParallelSupported, 0, 1) \
On 2013/06/17 14:07:58, Yang wrote:
> Maybe rename to indicate that it's compilation-related. We also got parallel
> sweeping etc.

Done.

[palfia, 2013-06-17 16:27:53]

Committed as r15184.