cmd/go: default to "exe" build mode for windows -race
cmd/go: default to "exe" build mode for windows -race

This patch changes the default build mode from "pie" to "exe" when
building programs on windows with "-race" in effect. The Go command
already issues an error if users explicitly ask for -buildmode=pie in
combination with -race on windows, but wasn't revising the default
"pie" build mode if a specific buildmode was not requested.

Updates #53539.
Updates #35006.

Change-Id: I2f81a41a1d15a0b4f5ae943146175c5a1202cbe0
Reviewed-on: https://go-review.googlesource.com/c/go/+/416174
Reviewed-by: Alex Brainman <54ba58c8441b5eff861de6b4e5ee46baf086b142@gmail.com>
Reviewed-by: Cherry Mui <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Run-TryBot: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

golang/go,golang/go,nawawi/go,golang/go,nawawi/go,nawawi/go,golang/go,golang/go,golang/go,golang/go,nawawi/go,nawawi/go,golang/go,nawawi/go,nawawi/go,nawawi/go