runtime: fix GoroutineProfile stacks not getting null terminated
Fix a regression introduced in CL 572396 causing goroutine stacks not
getting null terminated.
This bug impacts callers that reuse the []StackRecord slice for multiple
calls to GoroutineProfile. See https://github.com/felixge/fgprof/issues/33
for an example of the problem.
Add a test case to prevent similar regressions in the future. Use null
padding instead of null termination to be consistent with other profile
types and because it's less code to implement. Also fix the
ThreadCreateProfile code path.
Fixes #69243
Change-Id: I0b9414f6c694c304bc03a5682586f619e9bf0588
Reviewed-on: https://go-review.googlesource.com/c/go/+/609815 Reviewed-by: Tim King <taking@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com>