Make parallel test launcher print output as it's written by the child.
Make parallel test launcher print output as it's written by the child.

Add protection against hang when the child leaks a process.

BUG=54098
TEST=none

Review URL: http://codereview.chromium.org/3360008

git-svn-id: http://src.chromium.org/svn/trunk/src@58741 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 22ba29c002ef841d6be8aba6caaa4d003f2bf915
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser