test double set_stack

see #12213

Author: Simn

std/js/_std/haxe/Exception.hx

@@ -113,7 +113,7 @@ class Exception extends NativeException {
 	@:noCompletion
 	function setProperty(name:String, value:Any):Void {
 		try {
-			js.lib.Object.defineProperty(this, name, {value:value});
+			js.lib.Object.defineProperty(this, name, {value:value, writable: true});
 		} catch(e:Exception) {
 			js.Syntax.code('{0}[{1}] = {2}', this, name, value);
 		}

tests/unit/src/unit/issues/Issue12213.hx

@@ -15,6 +15,8 @@ class Issue12213 extends Test {
 				Method("Class", "method"),
 				LocalFunction(0)
 			];
+			e.stack = [];
+			// test if we can set again because that might be a special case
 			e.stack = stack;
 			utest.Assert.same(stack, e.stack);
 		}