Remove the last set_sources_assignment_filter().

It did not trigger any failures since it was in an is_ios block.

Change-Id: I79092abcf8857d46983f2fb9d35942fb99b3f47c
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/74591
Reviewed-by: Hui Yingst <nigi@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/testing/test.gni b/testing/test.gni
index a5daf07..515add5 100644
--- a/testing/test.gni
+++ b/testing/test.gni
@@ -197,7 +197,6 @@
       testonly = true
 
       # See above call.
-      set_sources_assignment_filter([])
       forward_variables_from(invoker, "*", [ "testonly" ])
 
       # Provide sensible defaults in case invoker did not define any of those