Introduce Float32x4, Float64x2, Int32x4, Float32x4Array, Float64x2Array
and Int32x4Array data types, implement the SIMD operations on the
Float32x4, Float64x2 and Int32x4 with C++ runtime functions and implement
Float32x4Array, Float64x2Array and Int32x4Array element loading and storing.

Conflicts:
	include/v8.h
	src/arm/assembler-arm.h
	src/hydrogen-instructions.cc
	src/ia32/assembler-ia32.h
	src/ia32/lithium-codegen-ia32.cc
	src/types.cc
	src/types.h
	src/x64/assembler-x64.h
	src/x64/lithium-codegen-x64.cc
	src/x64/lithium-x64.cc
	src/x64/lithium-x64.h
Change Float32x4, Float64x2 and Int32x4 to JSObject.

Change runtime implementations to JavaScript in simd128.js.