runtime: Goexit on C-created thread report more useful error message
Fixes #68275
Change-Id: I47b7a2092f1b4d48aebf437db4e329815c956bb9
GitHub-Last-Rev:
b89bf3cab7f9f7611122f535914f2788564643c5
GitHub-Pull-Request: golang/go#69126
Reviewed-on: https://go-review.googlesource.com/c/go/+/609296
Reviewed-by: Tim King <taking@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>