Use __CFTSRRate in __CFNanosecondsToTSR.

On Windows, __CFTSRRate is in units of 100 ns. To get a CFTimeInterval
from mach_absolute_time therefore, we should divide by 1.0E7, not 1.0E9.
But this suggests we should be dividing by __CFTSRRate anyway.

Author: 3405691582

CoreFoundation/RunLoop.subproj/CFRunLoop.c

@@ -52,7 +52,7 @@ static inline uint64_t __CFNanosecondsToTSR(uint64_t ns) {
 #if TARGET_OS_MAC || TARGET_OS_LINUX
     return ns;
 #else
-    CFTimeInterval ti = ns / 1.0E9;
+    CFTimeInterval ti = ns / __CFTSRRate;
     return __CFTimeIntervalToTSR(ti);
 #endif
 }