CI: disable ccache for MacOS builds

ccache is segfaulting in CI on MacOS

.github/workflows/macos_build.yml

@@ -161,22 +161,6 @@ jobs:
           fi
           Tools/environment_install/install-prereqs-mac.sh -y
           source ~/.bash_profile
-      # Put ccache into github cache for faster build
-      - name: Prepare ccache timestamp
-        id: ccache_cache_timestamp
-        shell: bash
-        run: |
-          NOW=$(date -u +"%F-%T")
-          echo "timestamp=${NOW}" >> $GITHUB_OUTPUT
-      - name: ccache cache files
-        uses: actions/cache@v4
-        with:
-          path: ~/.ccache
-          key: ${{github.workflow}}-ccache-${{matrix.config}}-${{steps.ccache_cache_timestamp.outputs.timestamp}}
-          restore-keys: ${{github.workflow}}-ccache-${{matrix.config}} # restore ccache from either previous build on this branch or on master
-      - name: setup ccache
-        run: |
-          . .github/workflows/ccache.env
       - name: test build ${{matrix.config}}
         env:
           CI_BUILD_TARGET: ${{matrix.config}}
@@ -189,5 +173,3 @@ jobs:
           ./waf
           ./waf configure --board ${{matrix.config}} --debug
           ./waf
-          ccache -s
-          ccache -z