Don't call config->setLogger(nullptr) directly to avoid having no logger at all

Summary:
Changelog: [Internal][Yoga] Don't call config->setLogger(nullptr) directly to avoid having no logger at all

Broken in D14151037 (05f36a835a) when it started calling
```
config->setLogger(nullptr);
```
instead of going thru
```
YGConfigSetLogger(config, nullptr);
```
which does the right thing by setting the logger to its default value:
https://www.internalfb.com/intern/diffusion/FBS/browsefile/master/xplat/yoga/yoga/Yoga.cpp?commit=835911317e8b3cf7da1866e40e1c79cda0690136&lines=4320-4330

Also by default YogaConfig always have a logger:
https://www.internalfb.com/intern/diffusion/FBS/browsefile/master/xplat/yoga/yoga/Yoga.cpp?commit=835911317e8b3cf7da1866e40e1c79cda0690136&lines=335-343

Reviewed By: SidharthGuglani

Differential Revision: D22387459

fbshipit-source-id: 4da91da87a696d38cc9d8db2acb5845d29398adb

java/jni/YGJNIVanilla.cpp

@@ -196,7 +196,7 @@ static void jni_YGConfigSetLoggerJNI(
       delete context;
       YGConfigSetContext(config, nullptr);
     }
-    config->setLogger(nullptr);
+    YGConfigSetLogger(config, nullptr);
   }
 }
 

java/tests/com/facebook/yoga/YogaLoggerTest.java

@@ -9,10 +9,62 @@ package com.facebook.yoga;
 
 import org.junit.Test;
 import java.lang.ref.WeakReference;
+import java.util.List;
+import java.util.ArrayList;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
 public class YogaLoggerTest {
+
+  @Test
+  public void testRemovingLoggerFromConfig() throws Exception {
+    final List<String> logs = new ArrayList<>();
+
+    final YogaConfig config = YogaConfigFactory.create();
+    YogaLogger logger = new YogaLogger() {
+      @Override
+      public void log(YogaLogLevel level, String message) {
+        logs.add(message);
+      }
+    };
+    config.setLogger(logger);
+
+    final YogaNode root = YogaNodeFactory.create(config);
+    root.setFlexDirection(YogaFlexDirection.ROW);
+    root.setAlignItems(YogaAlign.BASELINE);
+
+    final YogaNode child1 = YogaNodeFactory.create(config);
+    root.addChildAt(child1, 0);
+
+    final YogaNode child2 = YogaNodeFactory.create(config);
+    child2.setBaselineFunction(new YogaBaselineFunction() {
+        public float baseline(YogaNode node, float width, float height) {
+          return Float.NaN;
+        }
+    });
+    root.addChildAt(child2, 1);
+
+    assertEquals(logs.size(), 0);
+    try {
+      root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+      fail("Expected calculateLayout to throw");
+    } catch (IllegalStateException e) {
+    }
+
+    assertEquals(logs.size(), 1);
+
+    config.setLogger(null);
+
+    try {
+      root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+      fail("Expected calculateLayout to throw again");
+    } catch (IllegalStateException e) {
+    }
+
+    assertEquals(logs.size(), 1);
+  }
+
   @Test
   public void testLoggerLeak() throws Exception {
     final YogaConfig config = YogaConfigFactory.create();