ci: use `-Cinstrument-coverage` instead of `-Zprofile` #1318

Job	Run time
cargo fmt --all -- --check	7s
cargo test (ubuntu-latest)	32s
cargo check (ubuntu-latest)	14s
cargo test (macOS-latest)	35s
cargo test (windows-latest)	2m 0s
Code coverage (ubuntu-latest, nightly, --all-features)	40s
cargo check (macOS-latest)	18s
cargo check (windows-latest)	2m 15s
cargo clippy -- -D warnings	26s
	7m 7s

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