[FIX] component: fix props comparison code

Before this commit, Owl had a bad interaction with the static
defaultProps code. The props comparison would be done with the new props
object (unmodified) and the current props object (with default props
applied), so the comparison would always return false, which in turn,
causes additional useless renderings.

This commit modifies component node to keep a reference to the
(unmodified) props object so we can compare it as expected.

tests/components/__snapshots__/rendering.test.ts.snap

@@ -1,5 +1,29 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`children, default props and renderings 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    const b2 = text(ctx['state'].value);
+    const b3 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`children, default props and renderings 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(\`child\`);
+  }
+}"
+`;
+
 exports[`force render in case of existing render 1`] = `
 "function anonymous(app, bdom, helpers
 ) {