Remove old GetTickCount() code path for Windows

Windows XP support was dropped since GHC 8.0 as per https://ghc.haskell.org/trac/ghc/wiki/WindowsGhc

In HsWord64 getMonotonicNSec() on Windows we still fall back to the 32-bit GetTickCount() if QueryPerformanceFrequency() is not supported: Code

But Microsoft's documentation says that QueryPerformanceFrequency() is guaranteed to be supported on Windows >= XP:

On systems that run Windows XP or later, the function will always succeed and will thus never return zero.

Thus we can remove the if (!qpc_supported) check and all if (!qpc_frequency.QuadPart) code paths, and replace it with an assertion or a ./configure check.

We can also add a comment that getMonotonicNSec() will indeed always make use of the whole 64-bit domain.

Trac metadata

Trac field	Value
Version	8.3
Type	Task
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	bgamari, nh2
Operating system
Architecture

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