Add @likely/@unlikely annotations for blocks (#4979) #3870

Job	Run time
test-ubuntu22	24m 23s
test-ubuntu22-tofino	53m 37s
test-ubuntu20 (Unity ON, GTest ON)	27m 28s
test-ubuntu20 (Unity OFF, GTest OFF)	54m 14s
	2h 39m 42s

Provide feedback