Relax --debug-code checks that runtime returns are not the hole

ia32, unlike the other architectures, includes a --debug-code check that
asserts that runtime functions do not return the hole.  However the new
SuspendJSGeneratorObject runtime does return the hole at times.

This CL adds a wee hack that only signals an error if the callee was not
SuspendJSGeneratorObject.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/13856011

Patch from Andy Wingo <wingo@igalia.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14437 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
First cut at API for ES6 ArrayBuffers

R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/13958007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14438 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Tell the GC prologues to construct RetainedObjectInfos only when needed.

The GC prologue is called by the GC, but also by the heap snapshotter. The
RetainedObjectInfos are only needed by the heap snapshotter, so it's wasteful to
construct them always. (And it will be even more wasteful when Blink migrates to
the new GC APIs, since after that point it no longer knows about object groups.)

BUG=

Review URL: https://codereview.chromium.org/14471028
Patch from Marja Hölttä <marja@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14439 ce2b1a6d-e550-0410-aec6-3dcde31c8c00