run.bash: drop 'export GOROOT' and its obsolete comment
The comment justifies exporting GOROOT by saying the api test needs it,
which was relevant back when it was added in CL
99870043, but isn't true
by now.
As of Go 1.8, GOPATH can be unset (https://go.dev/doc/go1.8#gopath).
At some point it also became okay to leave GOROOT unset, at least
whenever one is looking to use the default GOROOT tree of the go command
being executed and not intentionally changing it to a custom directory.
It's also not there in the .bat and .rc variants of this script.
Drop it.
Change-Id: Ibcb386c560523fcfbfec8020f90692dcfa5aa686
Reviewed-on: https://go-review.googlesource.com/c/go/+/480376
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>