[PGO][SampledInstr] Correct off by 1s and allow 100% sampling (#113350)

This corrects a couple off by ones related to the sampling of
**instrumented** counters, and enables setting 100% rates for burst
sampling (burst duration = period).

Off by ones:
Prior to this change it was impossible to set a period of 65535 because
this was converted to fast sampling which rollsover at USHRT_MAX + 1
(65536). Similarly the burst durations would collect burst duration + 1
counts as they used an ULE comparison.

100% sampling:
Although this is not useful for a productionized use case, it does allow
for more deterministic testing with the sampling checks in place. After
all the off by ones are fixed, allowing for 100% sampling is a matter of
letting burst duration = period.

0 files changed, 0 insertions, 0 deletions