PSI2IR KT-45022 object in LHS of compound assignment

compiler/testData/codegen/box/operatorConventions/kt45022.kt

@@ -0,0 +1,8 @@
+fun box(): String {
+    X += 1
+    return "OK"
+}
+
+object X {
+    operator fun plusAssign(any: Any) = Unit
+}