Expand C++ macros in tools/generate-runtime-tests.py to increase coverage

R=dslomov@chromium.org

Review URL: https://codereview.chromium.org/290513002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21340 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Move check for existence of generated tests from run-tests.py to presubmit.py

Inspired by https://codereview.chromium.org/275143002#msg3

R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/290023002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21341 ce2b1a6d-e550-0410-aec6-3dcde31c8c00