Run clippy with c-allocator and rust-allocator features

Author: bjorn3

.github/workflows/checks.yaml

@@ -132,8 +132,8 @@ jobs:
           - target: x86_64-unknown-linux-gnu
         features:
           - ""
-          # - '--no-default-features --features="c-allocator"'
-          # - '--no-default-features --features="std,rust-allocator"'
+          - '--no-default-features --features="c-allocator"'
+          - '--no-default-features --features="rust-allocator"'
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources