cmd/go: unskip TestScript/build_issue48319 on Windows

Now that we have newer C compilers on the Windows builders, they
should fully support reproducible builds.

Updates #35006.

Change-Id: I0a8995fe327067c9e73e5578c385ea01ae5dee5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/454504
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>

Author: Bryan C. Mills

src/cmd/go/testdata/script/build_issue48319.txt

@@ -3,7 +3,6 @@
 
 [short] skip
 [!cgo] skip
-[GOOS:windows] skip  # The Go Windows builders have an extremely out-of-date gcc that does not support reproducible builds; see https://go.dev/issue/50824.
 
 # This test is sensitive to cache invalidation,
 # so use a separate build cache that we can control.