Cache permission id to avoid allocating of new strings

Every request that comes from Jelly is checked against Permissions.
As result it leads to a call of `getId` method that produces the new string.
Usually it's not a problem, but in case of stop-the-world pause user requests are accumulated.
So, once pause is finished, we forcibly allocated tons of strings for
every request. That leads to new stop-the-world pause. (And this cycle
can repeat multiple times)