Fix overload resolution for the initialization of a multi-dimensional

array from a braced-init-list. There seems to be a core wording wart
here (it suggests we should be testing whether the elements of the init
list are implicitly convertible to the array element type, not whether
there is an implicit conversion sequence) but our prior behavior appears
to be a bug, not a deliberate effort to implement the standard as written.

llvm-svn: 169690