CI: ignore system_tests on earlier GCC versions #4274

Job	Run time
ubuntu-20.04 (non-mavsdk_server, non-superbuild)	7m 12s
ubuntu-20.04 (non-mavsdk_server, hunter)	4m 44s
ubuntu-22.04 (non-mavsdk_server, non-superbuild)	6m 8s
ubuntu-22.04 (non-mavsdk_server, hunter)	4m 16s
Coverage (ubuntu-22.04)	6m 24s
alpine 3.19.0 (musl)	11m 57s
ubuntu-24.04 (non-mavsdk_server, non-superbuild)	8m 49s
ubuntu-24.04 (non-mavsdk_server, hunter)	4m 27s
ubuntu-20.04 (package, non-mavsdk_server)	7m 39s
android-arm	6m 28s
ubuntu-22.04 (package, non-mavsdk_server)	6m 9s
linux-armv6	5m 44s
linux-armv6-musl	12m 26s
android-arm64	6m 44s
ubuntu-24.04 (package, non-mavsdk_server)	7m 27s
linux-armv7	5m 36s
linux-armv7l-musl	12m 34s
android-x86	6m 21s
linux-arm64	5m 47s
linux-arm64-musl	13m 30s
android-x86_64	6m 27s
linux-arm64-lts	5m 25s
ios	1h 20m 18s
ios_simulator_x64	10m 32s
ubuntu-24.04 (style and proto check)	2m 17s
macOS x64	15m 28s
ios_simulator_arm64	1h 41m 28s
ubuntu-20.04 (mavsdk_server, superbuild)	13m 59s
macOS arm64	7m 11s
ubuntu-22.04 (mavsdk_server, superbuild)	11m 48s
Windows	1h 23m 37s
macOS framework x64	22m 10s
ubuntu-24.04 (mavsdk_server, superbuild)	12m 43s
macOS framework arm64	7m 15s
ubuntu-24.04 (mavsdk_server, superbuild)	13m 11s
ubuntu-24.04 (mavsdk_server, superbuild)	12m 33s
iOS XCFramework	2m 59s
	9h 19m 43s

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