[workflows] Run CI when any file is changed, including clang/**

Upstream commit b89617d02d1c8a2701c1d3290d2ff45cd858ccde had deleted
.github/workflows/clang-tests.yml. This commit adapts the Classic Flang
workflows to run when any file is changed, including clang/**.

Author: bryanpkc

.github/workflows/llvm-tests.yml

@@ -8,15 +8,9 @@ on:
   push:
     branches:
       - 'release_*x'
-    paths:
-      - 'llvm/**'
-      - '.github/workflows/llvm-tests.yml'
   pull_request:
     branches:
       - 'release_*x'
-    paths:
-      - 'llvm/**'
-      - '.github/workflows/llvm-tests.yml'
 
 concurrency:
   # Skip intermediate builds: always.