[GR-57090] Add mandatory approvers for substratevm. #20223

Job	Run time
/substratevm on Windows	7m 38s
/compiler style,fullbuild,test JDK21	29m 47s
/compiler build,bootstraplite JDKlatest	4m 16s
/espresso style,fullbuild JDK21	14m 9s
/substratevm style,fullbuild JDK21	11m 29s
/substratevm build,helloworld,native_unittests JDKlatest	20m 12s
/substratevm build,debuginfotest JDKlatest	25m 3s
/substratevm hellomodule JDKlatest	4m 56s
/sulong style,fullbuild,sulongBasic JDK21	21m 44s
/truffle JDK21	33m 52s
/vm build,sulong JDKlatest	25m 55s
/vm build JDKlatest	16m 0s
	3h 35m 1s

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