"field": synthetic variable creation in accessors, codegen changed accordingly, a set of tests, relevant code fix (j2k)

compiler/testData/codegen/box/properties/field.kt

@@ -0,0 +1,10 @@
+var my: String = ""
+    get() = field + "K"
+    set(arg) {
+        field = arg
+    }
+
+fun box(): String {
+    my = "O"
+    return my
+}

compiler/testData/codegen/box/properties/fieldInClass.kt

@@ -0,0 +1,6 @@
+class My {
+    val my: String = "O"
+        get() = field + "K"
+}
+
+fun box() = My().my

compiler/testData/codegen/box/properties/fieldInsideField.kt

@@ -0,0 +1,13 @@
+abstract class Your {
+    abstract val your: String
+
+    fun foo() = your
+}
+
+val my: String = "O"
+    get() = field + object: Your() {
+        override val your = "K"
+            get() = field
+    }.foo()
+
+fun box() = my

compiler/testData/codegen/box/properties/fieldInsideNested.kt

@@ -0,0 +1,12 @@
+abstract class Your {
+    abstract val your: String
+
+    fun foo() = your
+}
+
+val my: String = "O"
+    get() = object: Your() {
+        override val your = field
+    }.foo() + "K"
+
+fun box() = my

compiler/testData/codegen/box/properties/fieldSimple.kt

@@ -0,0 +1,4 @@
+val x: String = "OK"
+    get() = field
+
+fun box() = x