Remove target files before manually copying the patched std files for checking binary size in CI.

Author: detly

.github/workflows/check-binary-size.yml

@@ -50,8 +50,8 @@ jobs:
           git add library/backtrace
           rm -rf build/x86_64-unknown-linux-gnu/stage0-std
           python3 x.py build library --stage 0
-          cp -r ./build/x86_64-unknown-linux-gnu/stage0/bin ./build/x86_64-unknown-linux-gnu/stage0-sysroot/bin
-          cp -r ./build/x86_64-unknown-linux-gnu/stage0/lib/*.so ./build/x86_64-unknown-linux-gnu/stage0-sysroot/lib
+          cp -r --remove-destination ./build/x86_64-unknown-linux-gnu/stage0/bin ./build/x86_64-unknown-linux-gnu/stage0-sysroot/bin
+          cp -r --remove-destination ./build/x86_64-unknown-linux-gnu/stage0/lib/*.so ./build/x86_64-unknown-linux-gnu/stage0-sysroot/lib
           ./build/x86_64-unknown-linux-gnu/stage0-sysroot/bin/rustc -O foo.rs -o binary-updated
       - name: Display binary size
         run: |