Fix infinite loop in GridContainer layout
Fix infinite loop in GridContainer layout

I had a grid container and tried to set rect.min_height larger in the
editor; that caused an infinite loop in GridContainer::_notification
at line 118. The reason is max_index was being set to the *height* of
the row, not the *index* of the row. So later when it tried to erase
that row and try again, there was nothing to erase.
I applied the same fix to the width code.

RandomShaper/godot,groud/godot,Paulloz/godot,Faless/godot,groud/godot,sanikoyes/godot,guilhermefelipecgs/godot,okamstudio/godot,okamstudio/godot,godotengine/godot,guilhermefelipecgs/godot,groud/godot,akien-mga/godot,guilhermefelipecgs/godot,Shockblast/godot,firefly2442/godot,ZuBsPaCe/godot,BastiaanOlij/godot,Faless/godot,akien-mga/godot,vnen/godot,josempans/godot,mcanders/godot,josempans/godot,BastiaanOlij/godot,ex/godot,vkbsb/godot,MarianoGnu/godot,vkbsb/godot,akien-mga/godot,honix/godot,groud/godot,Paulloz/godot,Paulloz/godot,vnen/godot,josempans/godot,firefly2442/godot,Valentactive/godot,sanikoyes/godot,josempans/godot,Paulloz/godot,firefly2442/godot,Valentactive/godot,Zylann/godot,BastiaanOlij/godot,firefly2442/godot,sanikoyes/godot,NateWardawg/godot,BastiaanOlij/godot,honix/godot,mcanders/godot,akien-mga/godot,godotengine/godot,sanikoyes/godot,josempans/godot,vkbsb/godot,godotengine/godot,ZuBsPaCe/godot,ZuBsPaCe/godot,Shockblast/godot,Shockblast/godot,godotengine/godot,okamstudio/godot,ex/godot,RandomShaper/godot,ZuBsPaCe/godot,mcanders/godot,pkowal1982/godot,firefly2442/godot,pkowal1982/godot,honix/godot,guilhermefelipecgs/godot,pkowal1982/godot,Zylann/godot,pkowal1982/godot,MarianoGnu/godot,Shockblast/godot,godotengine/godot,vnen/godot,mcanders/godot,MarianoGnu/godot,Faless/godot,ZuBsPaCe/godot,sanikoyes/godot,ex/godot,MarianoGnu/godot,guilhermefelipecgs/godot,NateWardawg/godot,pkowal1982/godot,RandomShaper/godot,pkowal1982/godot,MarianoGnu/godot,Paulloz/godot,Valentactive/godot,DmitriySalnikov/godot,Zylann/godot,DmitriySalnikov/godot,vkbsb/godot,MarianoGnu/godot,okamstudio/godot,BastiaanOlij/godot,Zylann/godot,Zylann/godot,Paulloz/godot,firefly2442/godot,firefly2442/godot,Shockblast/godot,Shockblast/godot,akien-mga/godot,mcanders/godot,guilhermefelipecgs/godot,vnen/godot,Valentactive/godot,NateWardawg/godot,ZuBsPaCe/godot,Zylann/godot,akien-mga/godot,vnen/godot,Paulloz/godot,sanikoyes/godot,okamstudio/godot,godotengine/godot,okamstudio/godot,sanikoyes/godot,mcanders/godot,groud/godot,DmitriySalnikov/godot,MarianoGnu/godot,Faless/godot,ZuBsPaCe/godot,vkbsb/godot,akien-mga/godot,okamstudio/godot,guilhermefelipecgs/godot,RandomShaper/godot,vnen/godot,ex/godot,guilhermefelipecgs/godot,godotengine/godot,ex/godot,Valentactive/godot,DmitriySalnikov/godot,groud/godot,Zylann/godot,ex/godot,pkowal1982/godot,ex/godot,honix/godot,RandomShaper/godot,vkbsb/godot,Faless/godot,Zylann/godot,RandomShaper/godot,Faless/godot,okamstudio/godot,NateWardawg/godot,Valentactive/godot,pkowal1982/godot,Valentactive/godot,godotengine/godot,RandomShaper/godot,akien-mga/godot,Shockblast/godot,NateWardawg/godot,DmitriySalnikov/godot,Shockblast/godot,honix/godot,vnen/godot,DmitriySalnikov/godot,BastiaanOlij/godot,vkbsb/godot,honix/godot,NateWardawg/godot,firefly2442/godot,BastiaanOlij/godot,okamstudio/godot,MarianoGnu/godot,josempans/godot,DmitriySalnikov/godot,ZuBsPaCe/godot,Valentactive/godot,BastiaanOlij/godot,vnen/godot,NateWardawg/godot,Faless/godot,ex/godot,Faless/godot,okamstudio/godot,NateWardawg/godot,sanikoyes/godot,vkbsb/godot,josempans/godot,josempans/godot,NateWardawg/godot