os/exec: on Windows, suppress ErrDot if the implicit path matches the explicit one
If the current directory is also listed explicitly in %PATH%,
this changes the behavior of LookPath to prefer the explicit name for it
(and thereby avoid ErrDot).
However, in order to avoid running a different executable from what
would have been run by previous Go versions, we still return the
implicit path (and ErrDot) if it refers to a different file entirely.
Fixes #53536.
Updates #43724.
Change-Id: I7ab01074e21a0e8b07a176e3bc6d3b8cf0c873cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/414054 Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>