Implement in-place rehashing of HashTable.

The algorithm puts elements into correct positions in  multiple iterations.
On the first iteration it tries to put elements at entries specified by
their first hash probe. On the second iteration -- by the second
hash probe, and so on. Overall it does O(k*n) memory accesses, where
k is the maximum number of probes required for an element and n is the
capacity of the hash table. The expectation is that k will be small.

R=mstarzinger@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23658031

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16678 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "Clean up after r16292 (disable optimization for StringWrappers)."

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23600040

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16679 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "Fix phis for non-sse2 double values"

Need to investigate box2d regression.

BUG=
TBR=verwaest@chromium.org

Review URL: https://codereview.chromium.org/23437028

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16680 ce2b1a6d-e550-0410-aec6-3dcde31c8c00