Remove Latin-1 workaround on Bazel 6.4.0+

The fix for Latin-1 encoded files was landed in [6.4.0] after
being landed on Bazel [master].

We can conditionally use the old, unhermetic, `tar` workaround
on modern Bazel versions.

[master]: bazelbuild/bazel#18448
[6.4.0]: bazelbuild/bazel#19765

go/private/sdk.bzl

@@ -441,7 +441,10 @@ def _remote_sdk(ctx, urls, strip_prefix, sha256):
     # in Bazel 6.0.0+ (bazelbuild/bazel#16052). The only situation where
     # .zip files are needed seems to be a macOS host using a Windows toolchain
     # for remote execution.
-    if urls[0].endswith(".tar.gz"):
+    if (urls[0].endswith(".tar.gz") and
+        # Development versions of Bazel have an empty version string. We assume that they are
+        # more recent than the version that introduced the fix.
+        not versions.is_at_least("6.4.0", versions.get() or "6.4.0")):
         if strip_prefix != "go":
             fail("strip_prefix not supported")
         ctx.download(