Install deps only if needed for fuzzing

.github/workflows/rust.yml

@@ -29,8 +29,11 @@ jobs:
               AS_DEPENDENCY: true
               PIN_VERSIONS: true
     steps:
-      - name: Install test dependencies
+
+      - name: Install fuzz dependencies
         run: sudo apt-get update -y && sudo apt-get install -y binutils-dev libunwind8-dev libcurl4-openssl-dev libelf-dev libdw-dev cmake gcc libiberty-dev
+        env: ${{ matrix.env }}
+        if: ${{ env.DO_FUZZ == 'true' }}
       - name: Checkout Crate
         uses: actions/checkout@v2
       - name: Checkout Toolchain