Add missing Cargo.lock files and ext/ crate for Rust QL tools test fixtures #378

Job	Run time
CODEQL_PATH Tests (macos-latest)	1m 34s
CODEQL_PATH Tests (ubuntu-latest)	52s
CODEQL_PATH Tests (windows-latest)	1m 30s
Integration Tests (windows-latest, http)	25m 26s
Integration Tests (ubuntu-latest, stdio)	19m 15s
Integration Tests (ubuntu-latest, http)	16m 51s
Integration Tests (windows-latest, stdio)	27m 11s
	1h 32m 39s

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