Map HandleScope temp regs to S390 ones.
Remove unused PPC regs r17-19, r23-24.
Update lithium scratch register to be r1 on S390
Remap registers in JSEntry/JSEntryTrampoline/CEntryStub
Remap registers in MA::PushTryHandler()
Fix GE condition mask bug.
Remove some unnecessary PPC code causing intermittent failures.
Remove blr() and replace by Ret()
Remap r11 to r1 in BinaryOpStub::GenerateInt32Stub
Update caller/callee saved registers, remove r13_p-r16_p
Rename r20_p to cp and remove r20_p.
Remove deprecated r21_p
Add Assembler::breakpoint() and add to bdnz()