VS: Properly quote arguments in nasm.xml

Most arguments were quoted, but some weren't, causing problems if the
arguments contained whitespace.

In particular, the _STL_EXTRA_DISABLED_WARNINGS value takes spaces and
CMake's NASM support applies all add_definitions lines to NASM. The -D
flag is missing quotes, so projects using NASM and setting
_STL_EXTRA_DISABLED_WARNINGS break in the Visual Studio generator.

Likewise, the -o flag is missing quotes, which means filenames with
spaces do not work.

(The -U flag is unlikely to need quotes, but include them for
consistency.)

Extend the existing VSNASM test to cover these cases.

Tests/VSNASM/include/foo-proc.asm

@@ -3,5 +3,5 @@ foo:
 %else
 _foo:
 %endif
-    mov  	eax, 0
+    mov  	EAX_COMMA_SPACE_ZERO
     ret