Add JavaScript bindings for YGHasNewLayout (#1631)

Summary:
Adds JavaScript bindings for YGHasNewLayout which introduces
two new node methods: `hasNewLayout()` and `markLayoutSeen()`.

Closes https://github.com/facebook/yoga/issues/681

Pull Request resolved: https://github.com/facebook/yoga/pull/1631

Reviewed By: joevilches

Differential Revision: D55213296

Pulled By: NickGerleman

fbshipit-source-id: 161288c3f54c2b82a6b2b842387916fe8713c2c9

javascript/src/embind.cpp

@@ -177,6 +177,9 @@ EMSCRIPTEN_BINDINGS(YOGA_LAYOUT) {
       .function("markDirty", &Node::markDirty)
       .function("isDirty", &Node::isDirty)
 
+      .function("markLayoutSeen", &Node::markLayoutSeen)
+      .function("hasNewLayout", &Node::hasNewLayout)
+
       .function("calculateLayout", &Node::calculateLayout)
 
       .function("getComputedLeft", &Node::getComputedLeft)