Revert "enhance tests (mostly codegen)" temporarily

This reverts commit 95f9bcbacb.

compiler/testData/codegen/regressions/kt471.kt

@@ -1,3 +1,5 @@
+import java.util.ArrayList
+
 class MyNumber(val i: Int) {
     fun inc(): MyNumber = MyNumber(i+1)
 }
@@ -50,26 +52,25 @@ fun test6() : Boolean {
     return true
 }
 
-class MyArrayList<T>(var value: T) {
-    fun get(index: Int): T {
-        if (index != 17)
-            throw Exception()
-        return value
-    }
-    fun set(index: Int, value: T): Unit {
-        if (index != 17)
-            throw Exception()
-        this.value = value
-    }
-}
-
 fun test7() : Boolean {
-    var mnr  = MyArrayList<MyNumber>(MyNumber(42))
-    mnr[17]++
-    if (mnr[17].i  != 43) return false
+    var mnr  = ArrayList<MyNumber>()
+    mnr.add(MyNumber(42))
+    mnr[0]++
+    if (mnr[0].i  != 43) return false
     return true
 }
 
+fun test8() : Boolean {
+    var mnr  = ArrayList<MyNumber>()
+    mnr.add(MyNumber(42))
+    mnr.add(MyNumber(41))
+    mnr[1] = mnr[0]++
+    if (mnr[0].i  != 43) return false
+    if (mnr[1].i  != 42) return false
+    return true
+}
+
+
 fun box() : String {
     var m  = MyNumber(42)
 
@@ -81,6 +82,7 @@ fun box() : String {
     if (!test5()) return "fail test 5"
     if (!test6()) return "fail test 6"
     if (!test7()) return "fail test 7"
+    if (!test8()) return "fail test 8"
 
 
     ++m

compiler/testData/codegen/regressions/kt475.jet

@@ -14,5 +14,5 @@ var <T> ArrayList<T>.length : Int
     set(value: Int) = throw java.lang.Error()
 
 var <T> ArrayList<T>.last : T
-    get() = get(size()-1).sure()
+    get() = get(size()-1)
     set(el : T) { set(size()-1, el) }