Do not scavenge while marking incrementally when FLAG_gc_global is on.

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/281573002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21268 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "Read internal properties [[PromiseStatus]] and [[PromiseValue]] of the promise."

This reverts r21266.

TBR=danno@chromium.org

Review URL: https://codereview.chromium.org/273423008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21269 ce2b1a6d-e550-0410-aec6-3dcde31c8c00