With the simulator, MSan detects all memory accesses from JIT code
without the need for annotations.

We'd like to keep the annotation in the native (w/o simulator) mode
until we can move all MSan+V8 users to simulator mode.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/212833002

Patch from Evgeniy Stepanov <eugenis@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20399 ce2b1a6d-e550-0410-aec6-3dcde31c8c00