Added tests for null coalescing of nullables.
Added tests for null coalescing of nullables.

acourtney2015/JSIL,volkd/JSIL,antiufo/JSIL,volkd/JSIL,volkd/JSIL,iskiselev/JSIL,sander-git/JSIL,iskiselev/JSIL,iskiselev/JSIL,dmirmilshteyn/JSIL,antiufo/JSIL,sander-git/JSIL,sq/JSIL,volkd/JSIL,sander-git/JSIL,TukekeSoft/JSIL,Trattpingvin/JSIL,FUSEEProjectTeam/JSIL,FUSEEProjectTeam/JSIL,mispy/JSIL,hach-que/JSIL,antiufo/JSIL,dmirmilshteyn/JSIL,mispy/JSIL,sq/JSIL,TukekeSoft/JSIL,acourtney2015/JSIL,sq/JSIL,hach-que/JSIL,acourtney2015/JSIL,x335/JSIL,Trattpingvin/JSIL,sq/JSIL,TukekeSoft/JSIL,x335/JSIL,volkd/JSIL,sander-git/JSIL,antiufo/JSIL,x335/JSIL,acourtney2015/JSIL,TukekeSoft/JSIL,sq/JSIL,hach-que/JSIL,mispy/JSIL,hach-que/JSIL,x335/JSIL,Trattpingvin/JSIL,sander-git/JSIL,FUSEEProjectTeam/JSIL,Trattpingvin/JSIL,acourtney2015/JSIL,iskiselev/JSIL,iskiselev/JSIL,dmirmilshteyn/JSIL,hach-que/JSIL,FUSEEProjectTeam/JSIL,mispy/JSIL,dmirmilshteyn/JSIL,FUSEEProjectTeam/JSIL