Query Windows clock frequency and use reported max

Query Windows clock frequency and use reported max

Previously FIO used the Windows lower-bound clock frequency of 64 Hz for
its helper-thread. This caused IOPS/BW logs to have large drift between
timestamps when not using per-unit logging for those measurements.

Now query the current resolution and set to use the maximum for more
accurate timestamps. Note that the resolution is automatically restored
after FIO terminates.

Signed-off-by: Brandon Paupore <brandon.paupore@wdc.com>