Re-revert "Use unsigned type bitsets to limit undefined behaviour"

...and the various debug CLs.

R=machenbach@chromium.org
BUG=

Review URL: https://codereview.chromium.org/564413004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23955 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Only include compile-only win64 trybot in default set.

BUG=chromium:353487
LOG=n
R=jkummerow@chromium.org
TBR=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/570113002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23956 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/bleeding_edge' into bleeding_edge