DO NOT MERGE Crash app on foreground service notification error.

Resolved issue 118612296.

On any notification error, the NMS silently cancels the notification,
including foreground service notifications. Thus, an app could pass in a
garbage notification deliberately and start a foreground service silently.

This patch resolved this issue by judging the notification's flag, and if
it is a foreground notification, still crash the app as previous platforms,
and if it is a normal notification, don't crash the app.

Background: In 3ad4cdd1, which was merged into Android 9 release, the crash
behaviour is removed. But it is an important rule that foreground services
guaranteed to show an ongoing notification.

Test: Run the sample apk provided in the issue, it's main thread received
 a RemoteServiceException: Bad notification posted from package...
as intended behaviour.

Change-Id: I36ea0137ca6978ff401f64dccacb6f2edcadd7db
Merged-In: I36ea0137ca6978ff401f64dccacb6f2edcadd7db
Signed-off-by: Da Xing <qiyueliuhuo813@gmail.com>