Windows: add //tools/... tests to test suite

Add all tests under //tools/... to
//src:all_windows_tests, to run them on Bazel CI.

See https://github.com/bazelbuild/bazel/issues/4292

Closes #5839.

Change-Id: Iae647f561683cc50ef62416c4b834576ae918486
PiperOrigin-RevId: 208167743
diff --git a/tools/python/BUILD b/tools/python/BUILD
index ab09128..a344b44 100644
--- a/tools/python/BUILD
+++ b/tools/python/BUILD
@@ -31,3 +31,11 @@
     ],
     visibility = ["//tools:__pkg__"],
 )
+
+test_suite(
+    name = "all_windows_tests",
+    tests = [
+        "//tools/python/runfiles:all_windows_tests",
+    ],
+    visibility = ["//tools:__pkg__"],
+)