Correct occlusion distance calc for non-isometric tilesets #90574

Job	Run time
matrix-variables	1s
skip-duplicates-code	7s
skip-duplicates-data	6s
Basic Build and Test (Clang 10, Ubuntu, Curses)	39m 49s
Clang 14, macOS 12, Tiles, Sound, x64 and arm64 Universal Binary	1h 14m 47s
GCC 9, Curses, LTO	57m 20s
Clang 12, Ubuntu, Tiles, ASan	2h 8m 21s
GCC 11, Ubuntu, Curses, ASan	2h 16m 41s
GCC 12, Ubuntu cross-compile to MinGW-Win64, Tiles, Sound	1h 7m 56s
GCC 9, Ubuntu, Tiles, Sound, CMake	18m 40s
emscripten / Build	2h 11m 20s
	10h 55m 8s

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