Merge K2 box tests to main box tests

compiler/testData/codegen/box/properties/backingField/explicitBackingFieldInAnonymous.kt

@@ -0,0 +1,62 @@
+// TARGET_BACKEND: JVM_IR
+// IGNORE_BACKEND_K1: JVM_IR
+
+interface I {
+    val number: Number
+}
+
+fun test1(): String? {
+    val it = object : I {
+        final override val number: Number
+            field = 10
+
+        val next get() = number + 1
+    }
+
+    return if (it.next != 11) {
+        "[1] ${it.number}, ${it.next}"
+    } else {
+        null
+    }
+}
+
+fun test2(): String? {
+    class Local : I {
+        final override val number: Number
+            internal field = 42
+    }
+
+    return if (Local().number + 3 != 45) {
+        "[2] " + Local().number.toString()
+    } else {
+        null
+    }
+}
+
+fun test3(): String? {
+    val it = object : I {
+        override val number: Number
+            field = "100"
+            get() {
+                return field.length
+            }
+    }
+
+    return if (it.number != 3) {
+        "[3] " + it.number.toString()
+    } else {
+        null
+    }
+}
+
+fun box(): String {
+    val problem = test1()
+        ?: test2()
+        ?: test3()
+
+    return if (problem != null) {
+        "fail: " + problem
+    } else {
+        "OK"
+    }
+}