ci: update hash_validation_tests to slower_tests in more_extensive_but_slower_tests_ci.yml, after the repo name change

Author: spytheman

.github/workflows/more_extensive_but_slower_tests_ci.yml

@@ -39,5 +39,5 @@ jobs:
 
       - name: Run additional crypto tests
         run: |
-          v retry -- git clone --depth 1 https://github.com/vlang/hash_validation_tests
-          v test hash_validation_tests/
+          v retry -- git clone --depth 1 https://github.com/vlang/slower_tests
+          v test slower_tests/