Move remaining regression test data file to new folder, cleanup README (#1646)

Author: bittner

util/regression-tests/tests/REQUEST-921-PROTOCOL-ATTACK/921190.yaml renamed to tests/regression/tests/REQUEST-921-PROTOCOL-ATTACK/921190.yaml

@@ -5,10 +5,3 @@ Docker Support
 ==============
 A Dockerfile can be found in the docker/ directory, along with additional
 notes in docker/README.md
-
-Regression Tests
-================
-The regression tests
-are in the
-util/regression-tests
-folder.