Implement Percentage support for gap styles (#1643)

Summary:
X-link: https://github.com/facebook/react-native/pull/44067

X-link: https://github.com/facebook/litho/pull/980

Pull Request resolved: https://github.com/facebook/yoga/pull/1643

Changelog [Internal]:
- Added percentage value for flex layout gap
- Wired up to pass proper available width and height to implement this feature

Reviewed By: NickGerleman

Differential Revision: D56002340

fbshipit-source-id: c0bc86ac70a1391f115c87da99c2ef411535f68b

java/com/facebook/yoga/YogaNodeJNIBase.java

@@ -721,4 +721,9 @@ public abstract class YogaNodeJNIBase extends YogaNode implements Cloneable {
   public void setGap(YogaGutter gutter, float gapLength) {
     YogaNative.jni_YGNodeStyleSetGapJNI(mNativePointer, gutter.intValue(), gapLength);
   }
+
+  @Override
+  public void setGapPercent(YogaGutter gutter, float gapLength) {
+    YogaNative.jni_YGNodeStyleSetGapPercentJNI(mNativePointer, gutter.intValue(), gapLength);
+  }
 }