[tests] dodge

see #10565

std/php/Lib.hx

@@ -98,7 +98,7 @@ class Lib {
 		return @:privateAccess Array.wrap(a);
 	}
 
-	public static function hashOfAssociativeArray<T>(arr:NativeAssocArray<T>):Map<String, T> {
+	public static function hashOfAssociativeArray<T>(arr:NativeAssocArray<T>):StringMap<T> {
 		var result = new StringMap();
 		@:privateAccess result.data = arr;
 		return result;

tests/misc/projects/Issue10039/compile-fail.hxml.stderr

@@ -1 +1 @@
-Main.hx:2: characters 41-43 : Type parameters of multi type abstracts must be known (for haxe.IMap<Unknown<0> : String, Int>)
+Main.hx:2: characters 41-43 : Type parameters of multi type abstracts must be known (for haxe.IMap<Unknown<0>, Int>)