PSI2IR: generate IrEnumConstructorCalls with correct return type

Normally, the fact that is was Unit was not visible as enum constructors
are lowered to normal class constructors anyway. The exception is when
the arguments are reordered, causing the incorrect return type to leak
into the block that holds temporary variables.

compiler/testData/codegen/box/enum/constructorWithReordering.kt

@@ -0,0 +1,10 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// IGNORE_BACKEND: JS
+fun f(): String = "O"
+fun g(): String = "K"
+
+enum class E(val x: String, val y: String) {
+    A(y = g(), x = f())
+}
+
+fun box(): String = E.A.x + E.A.y