runtime: make ncgocall a global counter
ncgocall was stored per M, runtime.NumCgoCall lost the counter when a M die.
Fixes #46789
Change-Id: I85831fbb2713f4c30d1800d07e1f47aa0031970e
GitHub-Last-Rev:
cbc15fa870de776d3fbf3b62fc9a5e01792e6a26
GitHub-Pull-Request: golang/go#46842
Reviewed-on: https://go-review.googlesource.com/c/go/+/329729
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Alexander Rakoczy <alex@golang.org>