go link: use external linker when in race mode

As of clang 15.0.3 (via zig v0.10), when building with `race = "on"` on
x86_64 Linux, we observe the following:

    runtime/cgo(.text): relocation target memset not defined

Using an external linker when in race mode fixes that. Previously
`linkmode=external` was set for windows-only race builds, now lets just
apply it indiscriminately.

From my past experience, reporting a Go linker error when the external
linker works has a high chance to get the ticket closed as unactionable;
so it makes sense to just use an external linker, when it works.

go/private/actions/link.bzl

@@ -96,16 +96,18 @@ def emit_link(
         tool_args.add("-msan")
     if ((go.mode.static and not go.mode.pure) or
         go.mode.link != LINKMODE_NORMAL or
-        go.mode.goos == "windows" and (go.mode.race or go.mode.msan)):
+        go.mode.race or
+        go.mode.goos == "windows" and go.mode.msan)):
         # Force external linking for the following conditions:
         # * Mode is static but not pure: -static must be passed to the C
         #   linker if the binary contains cgo code. See #2168, #2216.
         # * Non-normal build mode: may not be strictly necessary, especially
         #   for modes like "pie".
-        # * Race or msan build for Windows: Go linker has pairwise
-        #   incompatibilities with mingw, and we get link errors in race mode.
-        #   Using the C linker avoids that. Race and msan always require a
-        #   a C toolchain. See #2614.
+        # * Msan build for Windows: Go linker has pairwise incompatibilities
+        #   with mingw. Using the C linker avoids that. Race and msan always
+        #   require a C toolchain. See #2614.
+        # * Race builds (previously Windows, later +linux): we get linker
+        #   errors during build with Go's internal linker.
         tool_args.add("-linkmode", "external")
     if go.mode.pure:
         # Force internal linking in pure mode. We don't have a C toolchain,