[release-branch.go1.21] cmd/go: find GOROOT using os.Executable when installed to GOROOT/bin/GOOS_GOARCH
When running make.bash in a cross-compiled configuration
(for example, GOARCH different from GOHOSTARCH), cmd/go
is installed to GOROOT/bin/GOOS_GOARCH instead of GOROOT/bin.
That means that we need to look for GOROOT in both ../.. and ../../..,
not just the former.
Fixes #62144.
Updates #62119.
Updates #18678.
Change-Id: I283c6a10c46df573ff44da826f870417359226a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/521015
Reviewed-by: Michael Matloob <matloob@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
(cherry picked from commit
9e9556d328c53ed0a4d8b36feee949885d648ba8)
Reviewed-on: https://go-review.googlesource.com/c/go/+/521695
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>