github: Update llvm-mingw to 20260224 (LLVM 22.1.0)

This version comes with LLVM 22.1.0. This also updates the set
of libcxx tests (and sources) executed as part of CI, which includes
a fix for a test that could fail spuriously.

Signed-off-by: Martin Storsjö <martin@martin.st>

.github/workflows/build.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 001c4a8..847fdce 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,7 @@
         uses: actions/checkout@v4
         with:
           repository: mstorsjo/llvm-mingw
-          ref: 20250924
+          ref: 20260224
       - name: Check out the mingw-w64 version to be tested
         uses: actions/checkout@v4
         with:
@@ -41,7 +41,7 @@
           if [ "$src_crt" = "ucrtbase" ]; then
               src_crt=ucrt
           fi
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250924/llvm-mingw-20250924-$src_crt-$DISTRO.tar.xz
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20260224/llvm-mingw-20260224-$src_crt-$DISTRO.tar.xz
           tar -Jxf llvm-mingw-*.tar.xz
           rm llvm-mingw-*.tar.xz
           mkdir install
@@ -76,7 +76,7 @@
             if [ "$src_crt" = "ucrtbase" ]; then
                 src_crt=ucrt
             fi
-            curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250924/llvm-mingw-20250924-$src_crt-$arch.zip
+            curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20260224/llvm-mingw-20260224-$src_crt-$arch.zip
             unzip -q llvm-mingw-*.zip
             rm llvm-mingw-*.zip
             mv llvm-mingw-* llvm-mingw
@@ -148,7 +148,7 @@
         uses: actions/checkout@v4
         with:
           repository: mstorsjo/llvm-mingw
-          ref: 20250924
+          ref: 20260224
       - name: Run tests
         run: |
           ./run-tests.sh /llvm-mingw
@@ -201,7 +201,7 @@
         uses: actions/checkout@v4
         with:
           repository: mstorsjo/llvm-mingw
-          ref: 20250924
+          ref: 20260224
       - name: Checkout llvm-project
         run: |
           bash -c "CHECKOUT_ONLY=1 ./build-llvm.sh"
@@ -558,7 +558,7 @@
         uses: actions/checkout@v4
         with:
           repository: mstorsjo/llvm-mingw
-          ref: 20250924
+          ref: 20260224
       - name: Run tests
         run: |
           gcc test/hello.c -o hello.exe
@@ -599,7 +599,7 @@
             automake
       - name: Unpack toolchain
         run: |
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250924/llvm-mingw-20250924-${{ matrix.crt == 'ucrtbase' && 'ucrt' || ((matrix.crt == 'msvcrt' && startsWith(matrix.arch, 'a')) && 'ucrt') || matrix.crt }}-${{ (matrix.arch == 'arm64ec' || matrix.arch == 'armv7') && 'aarch64' || matrix.arch }}.zip
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20260224/llvm-mingw-20260224-${{ matrix.crt == 'ucrtbase' && 'ucrt' || ((matrix.crt == 'msvcrt' && startsWith(matrix.arch, 'a')) && 'ucrt') || matrix.crt }}-${{ (matrix.arch == 'arm64ec' || matrix.arch == 'armv7') && 'aarch64' || matrix.arch }}.zip
           unzip -q llvm-mingw-*.zip
           rm llvm-mingw-*.zip
           mv llvm-mingw-* /llvm-mingw