Add GetCachedArrayIndex to the Hydrogen instruction set and implement GetCachedArrayIndex in the lithium code generator. The x64 and ia32 code generators implementations abort in the chunk builder.

Review URL: http://codereview.chromium.org/6499014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6803 ce2b1a6d-e550-0410-aec6-3dcde31c8c00