Remove generated codegen tests, move all testData to box/

A single test file will be generated out of box/ directory

compiler/testData/codegen/box/labels/propertyAccessor.kt

@@ -0,0 +1,29 @@
+val Int.getter: Int
+    get() {
+        return this@getter
+    }
+
+var Int.setter1: Int = 2
+    get() {
+        return this@setter1
+    }
+    set(i: Int) {
+        $setter1 = this@setter1
+    }
+
+var Int.setter2: Int = 2
+    set(i: Int) {
+        $setter2 = this@setter2
+    }
+
+fun box(): String {
+    val i = 1
+    if (i.getter != 1) return "getter failed"
+
+    i.setter1 = 2
+    if (i.setter1 != 1) return "setter1 failed"
+    i.setter2 = 2
+    if (i.setter2 != 1) return "setter2 failed"
+
+    return "OK"
+}