[PORT] Optimizes `/proc/icon_exists()` #15898

Job	Run time
Start Gate	1s
Collect data and setup caches for other tasks	18s
Run Linters	2m 54s
Windows Build	2m 7s
Compile Maps	2m 21s
Integration Tests / run (blueshift) / Run Tests (blueshift; 514)	9m 56s
Integration Tests / run (deltastation) / Run Tests (deltastation; 514)	9m 28s
Integration Tests / run (boxstation) / Run Tests (boxstation; 514)	9m 45s
Integration Tests / run (graveyard) / Run Tests (graveyard; 514)	9m 45s
Integration Tests / run (kilostation) / Run Tests (kilostation; 514)	9m 11s
Integration Tests / run (icebox) / Run Tests (icebox; 514)	9m 59s
Integration Tests / run (multiz_debug) / Run Tests (multiz_debug; 514)	10m 4s
Integration Tests / run (metastation) / Run Tests (metastation; 514)	9m 22s
Integration Tests / run (ouroboros) / Run Tests (ouroboros; 514)	9m 38s
Integration Tests / run (runtimestation) / Run Tests (runtimestation; 514)	8m 29s
Integration Tests / run (theseus) / Run Tests (theseus; 514)	9m 19s
Integration Tests / run (tramstation) / Run Tests (tramstation; 514)	9m 30s
Integration Tests / run (voidraptor) / Run Tests (voidraptor; 514)	9m 17s
Alternate Tests / run (515, 1642, runtimestation) / Run Tests (515.1642; runtimestation; 514)	8m 29s
Alternate Tests / run (516, 1652, runtimestation, 516) / Run Tests (516.1652; runtimestation; 516)	8m 31s
Compare Screenshot Tests	1s
Completion Gate	1s
	2h 28m 26s

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