8168417: Pending exceptions in java.base/windows/native/libnio

Reviewed-by: chegar, alanb

src/windows/native/sun/nio/ch/FileDispatcherImpl.c

@@ -210,6 +210,7 @@ Java_sun_nio_ch_FileDispatcherImpl_write0(JNIEnv *env, jclass clazz, jobject fdo
 
     if ((h == INVALID_HANDLE_VALUE) || (result == 0)) {
         JNU_ThrowIOExceptionWithLastError(env, "Write failed");
+        return IOS_THROWN;
     }
 
     return convertReturnVal(env, (jint)written, JNI_FALSE);
@@ -258,6 +259,7 @@ Java_sun_nio_ch_FileDispatcherImpl_writev0(JNIEnv *env, jclass clazz, jobject fd
 
     if ((h == INVALID_HANDLE_VALUE) || (result == 0)) {
         JNU_ThrowIOExceptionWithLastError(env, "Write failed");
+        return IOS_THROWN;
     }
 
     return convertLongReturnVal(env, totalWritten, JNI_FALSE);