github: Switch the linux-profile job to run on aarch64

The aarch64 runners are currently a fair bit faster than the x86_64
based ones.

This may marginally bias the profile, making it fit better for the
aarch64 build than for the x86_64 build, but this shouldn't make
a big difference in practice.

Author: mstorsjo

.github/workflows/build.yml

@@ -104,12 +104,12 @@ jobs:
 
   linux-profile:
     needs: [prepare, linux-stage1]
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-22.04-arm
     steps:
       - uses: actions/checkout@v4
       - uses: actions/download-artifact@v4
         with:
-          name: linux-stage1-ucrt-x86_64-toolchain
+          name: linux-stage1-ucrt-aarch64-toolchain
       - name: Unpack stage1 Clang
         run: |
           tar -Jxf llvm-mingw-*.tar.xz