Improve code and clarify parameters to ABI_Push/PopRegistersAndAdjustStack.

- Factor common work into a helper function.
- Replace confusingly named "noProlog" with "rsp_alignment".  Now that
x86 is not supported, we can just specify it explicitly as 8 for
clarity.
- Add the option to include more frame size, which I'll need later.
- Revert a change by magumagu in March which replaced MOVAPD with MOVUPD
on account of 32-bit Windows, since it's no longer supported.  True,
apparently recent processors don't execute the former any faster if the
pointer is, in fact, aligned, but there's no point using MOVUPD for
something that's guaranteed to be aligned...

(I discovered that GenFrsqrte and GenFres were incorrectly passing false
to noProlog - they were, in fact, functions without prologs, the
original meaning of the parameter - which caused the previous change to
break.  This is now fixed.)

Source/Core/VideoCommon/VertexLoader.cpp

@@ -584,7 +584,7 @@ void VertexLoader::CompileVertexTranslator()
 		PanicAlert("Trying to recompile a vertex translator");
 
 	m_compiledCode = GetCodePtr();
-	ABI_PushAllCalleeSavedRegsAndAdjustStack();
+	ABI_PushRegistersAndAdjustStack(ABI_ALL_CALLEE_SAVED, 8);
 
 	// Start loop here
 	const u8 *loop_start = GetCodePtr();
@@ -845,7 +845,7 @@ void VertexLoader::CompileVertexTranslator()
 	SUB(32, MatR(RAX), Imm8(1));
 
 	J_CC(CC_NZ, loop_start);
-	ABI_PopAllCalleeSavedRegsAndAdjustStack();
+	ABI_PopRegistersAndAdjustStack(ABI_ALL_CALLEE_SAVED, 8);
 	RET();
 #endif
 }