libFuzzer: Fix a leak in compile_filter() cleanup

This crash was found by running libFuzzer+ASan. Under some
circumstances, the cleanup performed in compile_filter() skips
free(3)-ing some things before returning. This change restructures the
function so the cleanup is always performed.

Bug: None
Test: make tests (with ASan)
Change-Id: I5fd22ecc6a400d7ef44ad0c1ccfcd2fafeaa04ed
2 files changed