runtime: fix dead link in gcc_androd.c file
runtime: fix dead link in gcc_androd.c file

Old url 404s because the file no longer exists on master; change it to
point to the android 10 release branch.

Change-Id: If0f8b645f2c746f9fc8bbd68f4d1fe41868493ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/232809
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/go,CAFxX/go,akutz/go,cloudflare/go,akutz/go,cloudflare/go,nawawi/go,akutz/go,nawawi/go,CAFxX/go,nawawi/go,golang/go,nawawi/go,cloudflare/go,cloudflare/go,akutz/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,akutz/go,CAFxX/go,golang/go,golang/go,nawawi/go,nawawi/go,akutz/go,cloudflare/go,CAFxX/go,akutz/go,CAFxX/go,golang/go,CAFxX/go,golang/go,cloudflare/go,nawawi/go,akutz/go,cloudflare/go,CAFxX/go,golang/go