[SYCL][Driver] Fix Windows CL SYCL device library detection logic

[sarnex]

If it's no RDC, the extension will definitely be BC. We need to switch the condition order.

[mdtoguchi]

I know that this was already there - but it seems redundant. Would this be sufficient?

Suggested change

	else if (HostTC->getTriple().isWindowsMSVCEnvironment() &&
	C.getDriver().IsCLMode())
	else if (HostTC->getTriple().isWindowsMSVCEnvironment())

[sarnex]

Do we always use CL mode on windows for all possible compiler executables (icpx, dpcpp, clang, etc)? I thought some of them had different effects (like even with the same oneapi install, calling icpx vs clang++ in the compiler folder would set different flags like fastmath/inining/etc, and I thought CL mode might be one of them). If Windows doesn't always use CL mode or if we aren't sure I would prefer not to change this in this PR.

[mdtoguchi]

CL mode is tied to clang-cl, which is used on Windows in general. It also implies MSVC based targets (even when invoked on Linux). But of course, you can target MSVC with clang++ if you wanted, and vice-versa. Usage of clang++ on Windows also implies MSVC. I think this may cause a disconnect here. I'm fine with leaving it here and looking into an update later.

[sarnex]

Thanks, let me know if I should make an internal tracker for followup.