[libcxx] Bump clang version to v22 (#153264)

Clang tip of tree is now v22, so bump the versions based on that now
that we have an updated container image.

---------

Co-authored-by: Nikolas Klauser <nikolasklauser@berlin.de>

.github/workflows/libcxx-build-and-test.yaml

@@ -47,8 +47,8 @@ jobs:
           'generic-cxx26',
           'generic-modules'
         ]
-        cc: [  'clang-21' ]
-        cxx: [ 'clang++-21' ]
+        cc: [  'clang-22' ]
+        cxx: [ 'clang++-22' ]
         include:
           - config: 'generic-gcc'
             cc: 'gcc-15'
@@ -86,18 +86,18 @@ jobs:
           'generic-cxx20',
           'generic-cxx23'
         ]
-        cc: [ 'clang-21' ]
-        cxx: [ 'clang++-21' ]
+        cc: [ 'clang-22' ]
+        cxx: [ 'clang++-22' ]
         include:
           - config: 'generic-gcc-cxx11'
             cc: 'gcc-15'
             cxx: 'g++-15'
+          - config: 'generic-cxx26'
+            cc: 'clang-21'
+            cxx: 'clang++-21'
           - config: 'generic-cxx26'
             cc: 'clang-20'
             cxx: 'clang++-20'
-          - config: 'generic-cxx26'
-            cc: 'clang-19'
-            cxx: 'clang++-19'
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: ${{ matrix.config }}
@@ -167,8 +167,8 @@ jobs:
       - name: ${{ matrix.config }}
         run: libcxx/utils/ci/run-buildbot ${{ matrix.config }}
         env:
-          CC: clang-21
-          CXX: clang++-21
+          CC: clang-22
+          CXX: clang++-22
       - uses: actions/upload-artifact@26f96dfa697d77e81fd5907df203aa23a56210a8 # v4.3.0
         if: always()
         with: