misc/cgo/testsanitizers: deadlock in TestTSAN/tsan11 [1.17 backport]

[gopherbot]

@bcmills requested issue #53113 to be considered for backport to the next 1.17 minor release.

@gopherbot, please backport to Go 1.18 and 1.17. This is a test-only fix for a spurious deadlock.

[gopherbot]

Change https://go.dev/cl/408824 mentions this issue: [release-branch.go1.17] misc/cgo/testsanitizers: buffer the signal channel in TestTSAN/tsan11

[gopherbot]

Closed by merging 909881d to release-branch.go1.17.