cmd/go: skip gold-specific part of TestNoteReading if gold is unavailable
The test already contained logic to do this however it did not match
the error "cannot find 'ld'" which appears to be how gcc fails when
ld.gold is missing.
Fixes #22340.
Change-Id: I841248cc489b8fa72bc00a95000ad405f9ef8a4f
Reviewed-on: https://go-review.googlesource.com/72111
Run-TryBot: Michael Munday <mike.munday@ibm.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>