Let test runner rerun failures to test for flakes.

When enabled, this dynamically adds jobs that had failures back to the pool. Special json output for flakes will be handled in a separate CL.

BUG=374134
LOG=n
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/360113003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22143 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Postpone termination exceptions in debug scope.

R=yurys@chromium.org
BUG=v8:3408
LOG=Y

Review URL: https://codereview.chromium.org/353393002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22144 ce2b1a6d-e550-0410-aec6-3dcde31c8c00