execabs: isGo119ErrDot: use errors.Is instead of string-matching
execabs: isGo119ErrDot: use errors.Is instead of string-matching

Addresses the TODO added in CL 403256.

Change-Id: Iae44242e00b6a309cc0f1e336462bc2d4995a5e2
GitHub-Last-Rev: 1adfdb799489c068127e5088cd131dcca79d86df
GitHub-Pull-Request: golang/sys#142
Reviewed-on: https://go-review.googlesource.com/c/sys/+/448877
Auto-Submit: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@google.com>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@google.com>
Reviewed-by: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@google.com>

golang/sys,golang/sys,golang/sys