Stop next statements retuning null from blocks
Stop next statements retuning null from blocks

This commit makes next statements return nil by default, which is
the correct behaviour. Fixes 2 failing specs.

merongivian/opal,kachick/opal,gabrielrios/opal,gausie/opal,gabrielrios/opal,gausie/opal,suyesh/opal,iliabylich/opal,c42engineering/opal,domgetter/opal,fazibear/opal,gausie/opal,Ajedi32/opal,fazibear/opal,jannishuebl/opal,iliabylich/opal,jgaskins/opal,Mogztter/opal,jgaskins/opal,opal/opal,domgetter/opal,catprintlabs/opal,suyesh/opal,Mogztter/opal,Mogztter/opal,charliesome/opal,kachick/opal,Mogztter/opal,bbatsov/opal,opal/opal,wied03/opal,iliabylich/opal,catprintlabs/opal,suyesh/opal,c42engineering/opal,Flikofbluelight747/opal,fazibear/opal,Flikofbluelight747/opal,Ajedi32/opal,bbatsov/opal,Flikofbluelight747/opal,jannishuebl/opal,gabrielrios/opal,kachick/opal,bbatsov/opal,castwide/opal,opal/opal,wied03/opal,c42engineering/opal,merongivian/opal,charliesome/opal,jgaskins/opal,kachick/opal,castwide/opal,castwide/opal,Ajedi32/opal,merongivian/opal,catprintlabs/opal,wied03/opal,jannishuebl/opal,opal/opal