Implement package expressions2 #4196

Job	Run time
Prepare CodeQL unit test matrix	5s
Run unit tests (cpp, 2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4, ubuntu-latest-xl, codeql-...	1h 55m 57s
Run unit tests (c, 2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4, ubuntu-latest-xl, codeql-cl...	40m 50s
Validate test results	8s
	2h 37m 0s

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