Renames and wildcards should not be separated if they appear together

[liancheng]

When groupedImports is set to Explode, renames and wildcards should not be separated. Otherwise, the semantics change. Here's an example:

import java.util.{Deque => D, _}

val d0: D[Int] = ???
val d1: Deque[Int] = ??? // Should fail compilation

Currently, we explode them into two imports and get:

import java.util._
import java.util.{Deque => D}

val d0: D[Int] = ???
val d1: Deque[Int] = ??? // Now it compiles