Remove old branch logic from push scripts.

The old temporary branch is not needed anymore. All scripts create a different branch after creating the temporary branch.

This also fixes logging subprocesses and logs a warning to track down script failures due to wrong branches.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/266083003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
FLAG_max_new_space_size is in MB.

Plus, cleanup of the space - generation mess. More to do there...

BUG=
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/268073004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21148 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Set max new space size in tests to proper MB value.

Revert "Limit old space size in test which require a large new space."

This reverts commit r21103.

Revert "Remove max space limits in tests."

This reverts commit r21104.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/263103006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21149 ce2b1a6d-e550-0410-aec6-3dcde31c8c00