Remove unused methods from android.security.KeyStore

Remove methods from android.security.KeyStore that have no real callers.

The methods with @UnsupportedAppUsage could be called via reflection by
apps targeting an old SDK level.  But since there is no valid use case
for these and they were already replaced with stubs in Android 12,
removing them is allowed by the non-SDK interface policy.

Bug: 326508120
Test: presubmit
Change-Id: Id742604786e71a212244f7800b9c245cea193057