[llvm] [libc][workflow] improve ci coverage with windows-2025 and arm ubuntu (PR #123745)

[Aiden Grossman via llvm-commits]

================
@@ -11,12 +11,18 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-24.04
+    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         include:
-          - c_compiler: clang
+          - os: ubuntu-24.04
+            ccache-variant: sccache
+            c_compiler: clang
+            cpp_compiler: clang++
+          - os: ubuntu-24.04-arm
+            ccache-variant: ccache
+            c_compiler: clang
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boomanaiden154 wrote:

This is effectively what `CMAKE_{C,CXX}_COMPILER_LAUNCHER` do.

https://github.com/llvm/llvm-project/pull/123745