GCSampler - CountData calculated as negative causes exception

[lspangler584]

Description
When GCSampler tries to create a negative count metric the GCSampler shuts down.

Expected Behavior
Unclear why there would be a negative value, but even if it occurs the GCSampler should not shut down.

Steps to Reproduce
No repro available.

Recommendation
Since many of the count values are delta values from the prior value, intercept a negative value and record it as 0 in the event.
When doing so, add a log message (finest) indicating the Metric and requested value that was switched to 0.

Your Environment
GCSampler is used for .NET Framework applications. It is unclear but likely this is also an issue for the GCSamplerNetCore.

[lspangler584]

Duplicate of #264