fix(vm): avoid "index out of range" in `convertArgToGno` #3082

Job	Run time
setup	3s
Run Main (gnodev) / Go Build / generated	11s
Run Main (gnodev) / Go Linter / lint	42s
Run Main (gnodev) / Go Test / test	1m 6s
Run Main (gnofaucet) / Go Linter / lint	29s
Run Main (gnofaucet) / Go Build / generated	11s
Run Main (gnofaucet) / Go Test / test	46s
Run Main (gnokeykc) / Go Build / generated	8s
Run Main (gnokeykc) / Go Test / test	48s
Run Main (gnokeykc) / Go Linter / lint	34s
Run Main (gnomd) / Go Build / generated	5s
Run Main (gnomd) / Go Linter / lint	20s
Run Main (gnomd) / Go Test / test	29s
	5m 52s

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