fix tests

Author: odersky

tests/neg/alpha-override/B_1.java

@@ -1,5 +1,5 @@
 // Java
-public class B_1 extends A_1 {
+public class B_1 {
   public int bar() {
     return 2;
   }

tests/neg/alpha-override/C_2.scala

@@ -1,4 +1,4 @@
 import annotation.alpha
 class C extends B_1 {   // error: Name clash between defined and inherited member
-  @alpha("bar") override def foo(): Int = 3
+  @alpha("bar") def foo(): Int = 3
 }

tests/neg/alpha-override1/B_1.java

@@ -0,0 +1,6 @@
+// Java
+public class B_1 {
+  public int bar() {
+    return 2;
+  }
+}

tests/neg/alpha-override/D_3.scala renamed to tests/neg/alpha-override1/D_2.scala

@@ -1,6 +1,6 @@
 import annotation.alpha
 class D extends B_1 {
-  @alpha("bar") def foo(): Int = 3   // error: needs override
+  @alpha("bar") def foo(): Int = 3
 }
 class E extends B_1 {
   @alpha("baz") override def bar(): Int = 3 // error: cannot have an @alpha annotation since external names would be different