Merged r19591, r19599 into trunk branch.

HAllocate should never generate allocation code if the requested size does not fit into page. Regression test included.

Fix representation generalization for doubles.

BUG=347543
LOG=N
R=danno@google.com, danno@chromium.org

Review URL: https://codereview.chromium.org/181183007

git-svn-id: https://v8.googlecode.com/svn/trunk@19623 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/trunk' into trunk