[PORT] Optimizes `/proc/icon_exists()` #15894

Job	Run time
Start Gate	1s
Collect data and setup caches for other tasks	28s
Run Linters	2m 27s
Compile Maps	1m 17s
Windows Build	2m 8s
Alternate Tests / run (515, 1642, runtimestation) / Run Tests (515.1642; runtimestation; 514)	1m 56s
Alternate Tests / run (516, 1652, runtimestation, 516) / Run Tests (516.1652; runtimestation; 516)	1m 55s
Integration Tests / run (blueshift) / Run Tests (blueshift; 514)	1m 55s
Integration Tests / run (boxstation) / Run Tests (boxstation; 514)	1m 39s
Integration Tests / run (deltastation) / Run Tests (deltastation; 514)	1m 45s
Integration Tests / run (graveyard) / Run Tests (graveyard; 514)	1m 46s
Integration Tests / run (icebox) / Run Tests (icebox; 514)	1m 42s
Integration Tests / run (kilostation) / Run Tests (kilostation; 514)	1m 59s
Integration Tests / run (metastation) / Run Tests (metastation; 514)	1m 42s
Integration Tests / run (multiz_debug) / Run Tests (multiz_debug; 514)	1m 29s
Integration Tests / run (ouroboros) / Run Tests (ouroboros; 514)	1m 17s
Integration Tests / run (runtimestation) / Run Tests (runtimestation; 514)	1m 18s
Integration Tests / run (theseus) / Run Tests (theseus; 514)	1m 10s
Integration Tests / run (tramstation) / Run Tests (tramstation; 514)	1m 9s
Integration Tests / run (voidraptor) / Run Tests (voidraptor; 514)	1m 9s
Compare Screenshot Tests	1s
Completion Gate	1s
	30m 14s

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