Clean up tests a little bit

exec/CsePhi.java

-class cse_with_phis {
+class CsePhi {
         public static void main(String[] args) {
                 int i = 0;
                 int j = 0;

exec/UbLoopFun.mj

-class BlockvisitorFun {
+class UbLoopFun {
     public static void main(String args[]) {
         boolean b;
         while (b) {};

exec/UbSimpleArrayDeref.mj

-class Main {
+class UbSimpleArrayDeref {
     public static void main(String[] main) {
         int p = (new int[33][])[0][3];
         System.out.println(p);
     }
 }
-