Optimize UBSAN regex
Optimize UBSAN regex

Add line anchor to the UBSAN error pattern to improve regexp matching
performance.

akosthekiss/fuzzinator,akosthekiss/fuzzinator,renatahodovan/fuzzinator,akosthekiss/fuzzinator,renatahodovan/fuzzinator,renatahodovan/fuzzinator,akosthekiss/fuzzinator,renatahodovan/fuzzinator