functional-test: restore bigger time marging to ensure stability #5770

Job	Run time
Dart with AddressSanitizer	2m 54s
Android	5m 59s
Android-Kotlin	9m 37s
Dart	3m 9s
Swift on MacOS	8m 55s
C++	2m 28s
CMake toolchain tests for Android	6m 37s
Swift on Linux	4m 47s
	44m 26s

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