Replace cargo-kcov with grcov

cargo-kcov is no longer working as of rust toolchain version 1.71.0, as
it can no longer discover test executables. This is due to cargo
changing its verbose stdout printing to include the qualified path to
rustc, which causes cargo-kcov's string matching to fail.

See also kennytm/cargo-kcov#54

cargo-kcov has had its last commit in 2019, so replace it with
cargo-llvm-cov, which is actively maintained, and written for rust.

Signed-off-by: Patrick Roy <[email protected]>

build_container.sh

@@ -24,18 +24,18 @@ curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain "$RUST_TOOLCHAI
 # Use `git` executable to avoid OOM on arm64:
 # https://github.com/rust-lang/cargo/issues/10583#issuecomment-1129997984
 cargo --config "net.git-fetch-with-cli = true" \
-    install cargo-kcov critcmp cargo-audit cargo-fuzz
+    install critcmp cargo-audit cargo-fuzz
 rm -rf /root/.cargo/registry/
 
 # Install nightly (needed for fuzzing)
 rustup install --profile=minimal nightly
 rustup component add miri rust-src --toolchain nightly
+rustup component add llvm-tools-preview  # needed for coverage
 
 # Install other rust targets.
 rustup target add $(uname -m)-unknown-linux-musl
 
-# Install kcov.
-cargo kcov --print-install-kcov-sh | sh
+cargo install cargo-llvm-cov
 
 # Install libgpiod (required by vhost-device crate)
 pushd /opt