This ensures no illegal cookies are send to okhttp

When a website in a ReactNative WebView sets a cookie with an illegal
character, this cookie will automatically be added to any request to the
same domain.

This happens through:
BridgeInterceptor.java (l.84)
ReactCookieJarContainer.java (l.44)
JavaNetCookieJar.java (l.59)
ForwardingCookieHandler.java (l.57)
ForwardingCookieHandler.java (l.168)
CookieManager.java (l.39)

The BridgeInterceptor.java then tries to set a Cookie header, which
validates both keys and values, and then crashes.
okhttp3.6.0 Headers.java (l.320)

I would have expected that the IllegalArgumentException would have been
caught by JavaMethodRapper.java (l.376), because that's where the
NetworkingModule is triggered to build the okhttp request, but my guess
is that this is not caught, because IllegalArgumentException is not an
IOException. Interceptor can only throw IOExceptions.

ReactAndroid/src/main/java/com/facebook/react/modules/network/ReactCookieJarContainer.java

@@ -1,12 +1,14 @@
 package com.facebook.react.modules.network;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
 import javax.annotation.Nullable;
 
 import okhttp3.Cookie;
 import okhttp3.CookieJar;
+import okhttp3.Headers;
 import okhttp3.HttpUrl;
 
 /**
@@ -37,7 +39,17 @@ public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
   @Override
   public List<Cookie> loadForRequest(HttpUrl url) {
     if (cookieJar != null) {
-      return cookieJar.loadForRequest(url);
+      List<Cookie> cookies = cookieJar.loadForRequest(url);
+      ArrayList<Cookie> validatedCookies = new ArrayList<>();
+      for (Cookie cookie : cookies) {
+        try {
+          Headers.Builder cookieChecker = new Headers.Builder();
+          cookieChecker.add(cookie.name(), cookie.value());
+          validatedCookies.add(cookie);
+        } catch (IllegalArgumentException ignored) {
+        }
+      }
+      return validatedCookies;
     }
     return Collections.emptyList();
   }