Don't throw in socket_read if socket_read_all returns < 0

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2096720

Bug: 229813087
Merged-In: I2a04a799d3748c221f8555fa7afc40d73f0f392c
Change-Id: Ie1624980ed310dcc93c552edec04208a9538b210

core/jni/android_net_LocalSocketImpl.cpp

@@ -257,7 +257,7 @@ static jint socket_read (JNIEnv *env, jobject object, jobject fileDescriptor)
     err = socket_read_all(env, object, fd, &buf, 1);
 
     if (err < 0) {
-        jniThrowIOException(env, errno);
+        // socket_read_all has already thrown
         return (jint)0;
     }