fix multi cloned element lose props.children bug (#415)

Author: xxxiin

src/index.js

@@ -304,7 +304,7 @@ function cloneElement(element, props, ...children) {
 	let elementProps = element.attributes || element.props;
 	let node = h(
 		element.nodeName || element.type,
-		elementProps,
+		extend({}, elementProps),
 		element.children || elementProps && elementProps.children
 	);
 	// Only provide the 3rd argument if needed.

test/index.js

@@ -249,7 +249,9 @@ describe('preact-compat', () => {
 
 		it('should support props.children', () => {
 			let element = <foo children={<span>b</span>}></foo>;
-			expect(cloneElement(element)).to.eql(element);
+			let clone = cloneElement(element);
+			expect(clone).to.eql(element);
+			expect(cloneElement(clone).props.children).to.eql(element.props.children);
 		});
 
 		it('children take precedence over props.children', () => {