Ensure stack alignment in ARM port

Ensure stack alignment in ARM port

In the CEntryStub keep track of the actual skew from the correct alignment to ensure proper alignment before calling the runtime. Add checks to test the expected skew when running on hardware.

Use the PrepareCallCFunction/CallCFunction in a few other places.

Add check to the ARM simulator for correct alignment.

Add option --sim-stack-alignment to set the stack alignment in the simulator. Currntly only values 4 and 8 makes sense. 8 is the default to make snapshots generated with the simulator work on hardware requiring 8 byte stack alignment.
Review URL: http://codereview.chromium.org/1530043

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4425 ce2b1a6d-e550-0410-aec6-3dcde31c8c00