KT-1717 Don't make member visibility inherit when it is not declared explicitly

#KT-1717 Fixed

compiler/testData/codegen/controlStructures/forUserType.jet

@@ -78,25 +78,25 @@ fun box() : String {
 }
 
 class MyCollection1(): java.lang.Iterable<Int> {
-    override fun iterator(): java.util.Iterator<Int> = MyIterator()
+    public override fun iterator(): java.util.Iterator<Int> = MyIterator()
 
     class MyIterator(): java.util.Iterator<Int> {
         var k : Int = 5
 
-        override fun next() : Int = k--
-        override fun hasNext() = k > 0
-        override fun remove() {}
+        public override fun next() : Int = k--
+        public override fun hasNext() = k > 0
+        public override fun remove() {}
     }
 }
 
 class MyCollection2(): Iterable<Int> {
-    override fun iterator(): Iterator<Int> = MyIterator()
+    public override fun iterator(): Iterator<Int> = MyIterator()
 
     class MyIterator(): Iterator<Int> {
         var k : Int = 5
 
-        override fun next() : Int = k--
-        override val hasNext : Boolean
+        public override fun next() : Int = k--
+        public override val hasNext : Boolean
           get() = k > 0
     }
 }

compiler/testData/codegen/controlStructures/sync.jet

@@ -3,7 +3,7 @@ import java.util.concurrent.atomic.*
 
 fun thread(block: ()->Unit ) {
     val thread = object: Thread() {
-        override fun run() {
+        public override fun run() {
             block()
         }
     }