message: Use mold in GH actions for tests and tools
  [mold](https://github.com/rui314/mold) has significant better
  performance than llvm or gcc.
diff: @@ -100,6 +100,8 @@ jobs:
  profile: minimal
  toolchain: stable
  override: true
  + - name: Mold
  + uses: rui314/setup-mold@v1
  - name: Cache
  uses: Swatinem/rust-cache@v1
  - name: Checkout
  @@ -173,6 +175,8 @@ jobs:
  profile: minimal
  toolchain: stable
  override: true
  + - name: Mold
  + uses: rui314/setup-mold@v1
  - name: Cache
  uses: Swatinem/rust-cache@v1
  - name: Checkout
  