[2.2.15] Flats and textures with the same lump name prioritize the flat over the texture in a map

2.2.13:

2.2.14/2.2.15:

Might be related to #1392.

Test PK3: FlatTextureNameTest.pk3

added Bug Regression Rendering labels

mentioned in commit 68588a4a

changed milestone to %2.2.16

mentioned in merge request !2620 (merged)

mentioned in commit 3cd84dfc

closed with merge request !2620 (merged)

closed with commit 68588a4a