When performing name lookup for UnresolvedDeclRefExpr, if a
local declaration after use is detected, we check outer results
to see if we can find better matching candidates before raising
a use_local_before_declaration error.
Resolves: SR-7660.
used before declared but the declaration was also marked invalid. This would
end up diagnosing nothing and thus result in an obscure assert crash in SILGen
instead. Solution is just to diagnose the use-before-declaration always.
