Implement 64-bit MacroAssembler::probe support for Windows.

Implement 64-bit MacroAssembler::probe support for Windows.
https://bugs.webkit.org/show_bug.cgi?id=175724

Reviewed by Mark Lam.

Source/JavaScriptCore:

This is needed to enable the DFG. MSVC does no longer support inline assembly
for 64-bit, which means we have to put the code in an asm file.

* assembler/MacroAssemblerX86Common.cpp:
(JSC::booleanTrueForAvoidingNoReturnDeclaration): Deleted.
* jit/JITStubsMSVC64.asm:

Source/WTF:

Enable masm probe and DFG.

* wtf/Platform.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@221032 268f45cc-cd09-0410-ab3c-d52691b4dbfc