Rename tests/README.md

tests/README-TESTS.md

@@ -1,4 +1,4 @@
-- [Introduction](#introduction)
+- [README-TESTS](#README-TESTS)
   - [Running the test suite](#running-the-test-suite)
   - [Writing new tests](#writing-new-tests)
   - [Test suite](#test-suite)
@@ -23,7 +23,7 @@
 <!-- The TOC is generated by Markdown Preview Enhanced -->
 
 
-# Introduction
+# README-TESTS
 
 This test suite is intended for system tests, i.e. for running a binary with
 certain parameters and comparing the output against an expected value. This is