Slices: Apply the recent changes of Span to ReadOnlySpan.
Slices: Apply the recent changes of Span to ReadOnlySpan.

ahsonkhan/corefxlab,stephentoub/corefxlab,whoisj/corefxlab,VSadov/corefxlab,livarcocc/corefxlab,KrzysztofCwalina/corefxlab,Vedin/corefxlab,hanblee/corefxlab,adamsitnik/corefxlab,Vedin/corefxlab,stephentoub/corefxlab,alexperovich/corefxlab,adamsitnik/corefxlab,Vedin/corefxlab,ericstj/corefxlab,Vedin/corefxlab,ericstj/corefxlab,VSadov/corefxlab,VSadov/corefxlab,tarekgh/corefxlab,dotnet/corefxlab,nguerrera/corefxlab,KrzysztofCwalina/corefxlab,weshaggard/corefxlab,stephentoub/corefxlab,ericstj/corefxlab,benaadams/corefxlab,stephentoub/corefxlab,tarekgh/corefxlab,VSadov/corefxlab,stephentoub/corefxlab,ericstj/corefxlab,whoisj/corefxlab,hanblee/corefxlab,ravimeda/corefxlab,VSadov/corefxlab,ericstj/corefxlab,Vedin/corefxlab,joshfree/corefxlab,ericstj/corefxlab,joshfree/corefxlab,VSadov/corefxlab,benaadams/corefxlab,ahsonkhan/corefxlab,dotnet/corefxlab,Vedin/corefxlab,stephentoub/corefxlab