syscall: restore EscapeArg behavior for empty string
Accidentally broken by CL 259978.
For #41825
Change-Id: Id663514e6eefa325faccdb66493d0bb2b3281046
Reviewed-on: https://go-review.googlesource.com/c/go/+/260397
Trust: Ian Lance Taylor <iant@golang.org>
Trust: Alex Brainman <alex.brainman@gmail.com>
Trust: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>