Bump tests submodule

Signed-off-by: David Shah <dave@ds0.me>

tests

diff --git a/tests b/tests
index 6f93d3e..8f93e7e 160000
--- a/tests
+++ b/tests
@@ -1 +1 @@
-Subproject commit 6f93d3edb3cb3adab142a8d00eec0a7377faa864
+Subproject commit 8f93e7e0f897b1b5da469919c9a43ba28b623b2a