SDL: Fix scissor rect state when scissor test is disabled #750

Job	Run time
Rocky Linux	1m 43s
Rocky Linux MinGW	1m 1s
FreeBSD	1m 13s
iOS/tvOS SDL3 (iOS, iphoneos, arm64)	1m 8s
Rocky Linux MinGW SDL3	1m 7s
iOS/tvOS SDL3 (iOS, iphonesimulator, x86_64;arm64)	1m 1s
Debian Linux PPC	1m 45s
iOS/tvOS SDL3 (tvOS, appletvos, arm64)	49s
Debian Linux PPC SDL3	59s
iOS/tvOS SDL3 (tvOS, appletvsimulator, x86_64;arm64)	1m 1s
Rocky Linux SDL3	1m 18s
macOS (x86_64)	32s
macOS (Universal) SDL3	1m 24s
Windows (MSVC)	42s
	15m 43s

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