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

[Schrodinger ZHU Yifan 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
----------------
SchrodingerZhu wrote:

`sccache` is a modern implementation from Mozilla, it supports more storage format and compiler (e.g. `msvc/clang-cl`). I prefer to default on `sccache` but due to https://github.com/hendrikmuhs/ccache-action/issues/279, `ccache` is used on arm64 ubuntu.

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