DMA and Misc. Edge Case test results worse after running Layer Toggle test!

[CLS-StarkThyme]

mGBA test suite v0-r66 has a weird issue affecting all emulators (and possibly real hardware) where the results of the DMA and Misc. Edge Case tests look slightly worse after running the Layer Toggle test. On mGBA, 1232 of the 1252 DMA tests and 8 of the 10 Misc. Edge Case tests pass before the Layer Toggle test, then 1216 to 1232 of the 1252 DMA tests and 7 of the 10 Misc. Edge Case tests pass after the Layer Toggle test.

[CLS-StarkThyme]

As it turns out, even the Memory tests take a big hit after running the Layer Toggle test. The first run-through shows 1552 of 1552, then the second run-through shows 1488 of 1552.

[endrift]

Strangely I only get an additional 4 DMA test failures:

GBA Debug: DMA test: 0 Imm H V+BIOS/+VRAM
GBA Debug: 5: Got 01010101 vs 00000000: FAIL
GBA Debug: DMA test: 1 Imm H V+BIOS/+VRAM
GBA Debug: 5: Got 01010101 vs 00000000: FAIL
GBA Debug: DMA test: 2 Imm H V+BIOS/+VRAM
GBA Debug: 5: Got 01010101 vs 00000000: FAIL
GBA Debug: DMA test: 3 Imm H V+BIOS/+VRAM
GBA Debug: 5: Got 01010101 vs 00000000: FAIL

Having trouble reproducing the memory test issue.

[endrift]

Ok, I have a fix for the DMA test failure (eb6d373), but the memory test is (another) issue with how I'm handling save files (hopefully fixed or at least worked around in 86f4695), and the misc edge cases one I'm still investigating.