Render header/impl on properties in tests and diagnostic messages

As a side effect, header/impl and some other modifiers on functions are now
rendered in a different, more natural, order

compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.txt

@@ -1,6 +1,6 @@
 package
 
-public val bar2: kotlin.Int
+public impl val bar2: kotlin.Int
 public impl fun foo2(): kotlin.Int
 
 public impl interface Baz2 {