ZJIT: Use clang-16 for bindgen on CI

Since many of us developing ZJIT are on at least Clang 16 locally now
due to recent macOS update, let's use Clang 16 on CI, too. There is
some differences between https://github.com/llvm/llvm-project
Clang and Apple Clang, even when the version number match, but I figure
it's good to shrink the difference anyways.

Author: XrXr

.github/workflows/zjit-ubuntu.yml

@@ -69,12 +69,9 @@ jobs:
 
           - test_task: 'zjit-bindgen'
             hint: 'To fix: use patch in logs'
-            configure: '--enable-zjit=dev --with-gcc=clang-14'
-            libclang_path: '/usr/lib/llvm-14/lib/libclang.so.1'
-
-          - test_task: 'test-bundled-gems'
-            configure: '--enable-zjit=dev'
-            run_opts: '--zjit-call-threshold=1'
+            configure: '--enable-zjit=dev --with-gcc=clang-16'
+            clang_path: '/usr/bin/clang-16'
+            runs-on: 'ubuntu-24.04' # for clang-16
 
     env:
       GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
@@ -87,7 +84,7 @@ jobs:
       RUST_BACKTRACE: 1
       ZJIT_RB_BUG: 1
 
-    runs-on: ubuntu-22.04
+    runs-on: ${{ matrix.runs-on || 'ubuntu-22.04' }}
 
     if: >-
       ${{!(false
@@ -175,7 +172,7 @@ jobs:
           PRECHECK_BUNDLED_GEMS: 'no'
           SYNTAX_SUGGEST_TIMEOUT: '5'
           ZJIT_BINDGEN_DIFF_OPTS: '--exit-code'
-          LIBCLANG_PATH: ${{ matrix.libclang_path }}
+          CLANG_PATH: ${{ matrix.clang_path }}
           TESTS: ${{ matrix.test_all_opts }}
         continue-on-error: ${{ matrix.continue-on-test_task || false }}