Replace BuildFastElementAccess() with AddFastElementAccess().

This is trivial cleanup. All calls to BuildFastElementAccess() pass
the result to AddInstruction().

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/19759003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15789 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Add AssertSmi() in x64 MacroAssembler::SmiTest().

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/19647006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15790 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Replace BuildExternalArrayElementAccess() with AddExternalArrayElementAccess().

This is trivial cleanup. All calls to BuildExternalArrayElementAccess()
pass the result to AddInstruction().

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/19658004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15791 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
ES6: Implement WeakSet

WeakSets work similar to ordinary Sets but the value (which must be an
object) is held weakly.

This is available under --harmony-collections

BUG=v8:2785
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/19678023

Patch from Erik Arvidsson <arv@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15792 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Turn on parallel recompilation for tests that assert optimization status.

R=mvstanton@chromium.org
BUG=

Review URL: https://codereview.chromium.org/19807002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15793 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Prepare push to trunk.  Now working on version 3.20.8.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/19933002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15794 ce2b1a6d-e550-0410-aec6-3dcde31c8c00