Replace oneway shortcut api with AndroidFuture

Oneway calls to the system process can cause more trouble along those
lines than they solve.

Asynchronous incall pressure to the system process is worse than
synchronous incall pressure: it causes catastrophic failure modes
and is also much harder to diagnose when problems happen.
It's also much harder to guarantee transactionality when the caller
side is asynchronous.

Bug: 184878227
Test: atest ShortcutManagerTest1 ShortcutManagerTest2
ShortcutManagerTest3 ShortcutManagerTest4 ShortcutManagerTest5
ShortcutManagerTest6 ShortcutManagerTest7 ShortcutManagerTest8
ShortcutManagerTest9 ShortcutManagerTest10 ShortcutManagerTest11
Test: atest CtsShortcutManagerTestCases
Change-Id: I4ec6b188f079c018902bedf32198c04e9c45a60d

Change-Id: I854de382ee6bdc5ae32b6874b7d875dfe6c03c40