Refactor codegen tests

- initialize environment only once in setUp()
- add comments on why some tests are disabled
- modify and rename some tests
- re-enable now working tests
- extract some tests into files with box()
- remove useless 'throws' declarations and commented code

compiler/testData/codegen/super/basicproperty.kt

@@ -16,7 +16,9 @@ class N() : M() {
 
 fun box(): String {
     val n = N()
-    System.out?.println("a: " + n.a + " b: " + n.b + " superb: " + n.superb)
+    n.a
+    n.b
+    n.superb
     if (n.b == 3 && n.a == 4 && n.superb == 3) return "OK";
     return "fail";
-}
+}

compiler/testData/codegen/super/traitproperty.kt

@@ -23,7 +23,9 @@ class N() : M {
 
 fun box(): String {
     val n = N()
-    System.out?.println("a: " + n.a + " b: " + n.b + " superb: " + n.superb)
+    n.a
+    n.b
+    n.superb
     if (n.b == 3 && n.a == 4 && n.superb == 3) return "OK";
     return "fail";
-}
+}