Add windows_msvc back to conditions.

This is partial revert of 6d637f4.

windows_msvc condition is used downstream by tensorflow via ruy.

The culprit line is in https://github.com/google/ruy/blob/master/ruy/build_defs.bzl#L60 (and #L67,#L77).

Closes bazelbuild#12661.

PiperOrigin-RevId: 346353748

src/conditions/BUILD

@@ -149,6 +149,12 @@ config_setting(
     visibility = ["//visibility:public"],
 )
 
+config_setting(
+    name = "windows_msvc",
+    values = {"cpu": "x64_windows_msvc"},
+    visibility = ["//visibility:public"],
+)
+
 config_setting(
     name = "arm",
     constraint_values = ["@platforms//cpu:arm"],