Add //test:fileutils_unittests to //test:test_support_unittests deps.

The dependency has been accidentally removed in:
https://webrtc-review.googlesource.com/c/src/+/67161

Bug: None
Change-Id: I568a5d172ff327b31fe80227f5d0ed9f9fc8a93c
Reviewed-on: https://webrtc-review.googlesource.com/95485
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24395}
diff --git a/test/BUILD.gn b/test/BUILD.gn
index 187069c..b5ec01b 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -301,6 +301,7 @@
       ":direct_transport",
       ":fake_video_codecs",
       ":fileutils",
+      ":fileutils_unittests",
       ":perf_test",
       ":rtp_test_utils",
       ":test_common",