Remove now-redundant condition in sealedness checking

It arrived in c1f8dbc, but is no longer needed after user-defined
value classes were introduced in 2.10.0.

Author: retronym

src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala

@@ -115,7 +115,7 @@ trait TreeAndTypeAnalysis extends Debugging {
             )
           else None
         // make sure it's not a primitive, else (5: Byte) match { case 5 => ... } sees no Byte
-        case sym if sym.isSealed && !isPrimitiveValueClass(sym) =>
+        case sym if sym.isSealed =>
           val subclasses = debug.patmatResult(s"enum $sym sealed, subclasses")(
             // symbols which are both sealed and abstract need not be covered themselves, because
             // all of their children must be and they cannot otherwise be created.