PPC: handle large array accesses in optimized code.
PPC: Fix write barrier input in KeyedStoreIC::GenerateSloppyArguments.
PPC: optimize mov sequence for int16/int32 operands when applicable.
Clean up CODE_STUB_LIST_PPC.
PPC: optimize mov sequence for int64 operands when applicable.
PPC: Fix return value tracing in BE simulators.
PPC: Fix ObjectPair return handling in native 64-bit BE simulator.
PPC64: Fix return address relocation in CheckStackGuardState.
PPC64: Use 32-bit compare instructions for Non-Smi integer operations.

(continues initial support added in commit 7ead96da)
Cleanup endian-specific logic.

Make consistent use of V8_TARGET_BIG_ENDIAN / V8_TARGET_LITTLE_ENDIAN
macros rather than __BYTE_ORDER (which isn't defined on AIX).

Conflicts:

	build/toolchain.gypi
	src/globals.h
	src/ppc/builtins-ppc.cc
	src/ppc/lithium-codegen-ppc.cc
PPC: Simulator debugger fixes for 64-bit.
PPC: Add CheckEqualsHelper for intptr_t on 32-bit AIX.

This problem was visible only when building with nativesim=true on AIX.
PPC: Cleanup AIX-specific logic.

Make consistent use of V8_OS_AIX rather than _AIX.

Conflicts:

	src/atomicops.h
PPC: Tune OS::GetRandomMmapAddr for 64-bit platforms.

- AIX has 64 bits of virtual addressing, but we limit address range to
  avoid losing precision if address is stored as a double.  This
  fixes the EquivalenceOfLoggingAndTraversal test.

- Big-endian Linux has 44 bits of virtual addressing.

- Little-endian Linux has 48 bits of virtual addressing.

Conflicts:

	src/platform-aix.cc
Scale 1 MB incremental marking step size by kCodeSizeMultiplier.

This allows cctest/test-heap/ReleaseOverReservedPages to pass on PPC64.
AIX: add comment for pathological case in mmapHelper.
PPC64: Ensure DoAddI result is in range for Integer32 representation.
PPC: Pass scratch register to LoadP/StoreP to handle large offsets.

Conflicts:

	src/ppc/code-stubs-ppc.cc
	src/ppc/full-codegen-ppc.cc
PPC: Fix disassembly of internal references.

Conflicts:

	src/ppc/assembler-ppc.cc
	src/ppc/assembler-ppc.h