Disable concurrent osr when concurrent recompilation is disabled.

Also introduce a flag for a quick check that concurrency is on.

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/64543004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17570 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Allow redirecting disassembly and deoptimization traces into a file.

This is controlled by two flags:

--redirect_code_traces
--redirect_code_traces_to=<filename>

When redirection is enabled but --redirect_code_traces_to is not specified traces are written to a file code-<pid>-<isolate>.asm. This mangling scheme matches hydrogen.cfg and allows easy discovery of compilation artifacts in a multi-V8 environment (e.g. when compilation is traced from inside Chromium).

D8 defines --redirect_code_traces_to=code.asm similar to hydrogen.cfg redirection.

BUG=
R=danno@chromium.org

Review URL: https://codereview.chromium.org/43273004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17571 ce2b1a6d-e550-0410-aec6-3dcde31c8c00