Simplify Scope and ScopePtr conversions.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/643603002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24488 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Remove default NOP implementation of MonotonicallyIncreasingTime.

BUG=417668
LOG=N
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/641653002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24489 ce2b1a6d-e550-0410-aec6-3dcde31c8c00