Split neg test that emits errors in two phases

Author: nicolasstucki

tests/neg/erased-implicit-b.scala

@@ -0,0 +1,3 @@
+object Test {
+  def foo erased (implicit a: Double) = 42   // error
+}

tests/neg/erased-implicit.scala

@@ -6,5 +6,4 @@ object Test {
 
   erased implicit def doubleImplicit: Double = 42.0
 
-  def foo erased (implicit a: Double) = 42   // error
 }