Mark foundations_test as flaky

--
MOS_MIGRATED_REVID=140361154
diff --git a/src/test/java/com/google/devtools/build/lib/BUILD b/src/test/java/com/google/devtools/build/lib/BUILD
index e62da8d..23106e9 100644
--- a/src/test/java/com/google/devtools/build/lib/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/BUILD
@@ -136,6 +136,7 @@
         ] + ALL_WINDOWS_TESTS,
     ),
     data = glob(["vfs/*.zip"]),
+    flaky = True,
     tags = [
         "foundations",
         "no_windows",