Preserve implicit split-permissions on clear.

The platform implicitly issues a grant for new runtime permissions
which have been split from non-runtime permissions, but we discovered
that clearing data on an app will remove this implicit grant.

This change fixes that bug by preserving any implicit grants
during a resetRuntimePermissions() as long as the app being cleared
is still targeting an older SDK.

Bug: 183203469
Test: csuite-tradefed run commandAndExit csuite-app-launch --enable-module-dynamic-download --dynamic-download-args com.android.csuite.config.AppRemoteFileResolver:uri-template=/tmp/csuite-apk/{package} -l verbose --package com.skype.raider
Change-Id: I4afd59d6cc32cdd8916be1ceba5e01fd07832d1a