fix(pdk) get_phases_names wrong lshift

[chronolaw]

Summary

PHASES.n means lshift times, but now it equals to 13, it is 0x2000，
but the max phases admin_api is 0x10000000,
so the function get_phases_names can not get the right name.

I change the PHASES.n to 30, then we can support the all phases bits.

Full changelog

• change PHASES.n to 30, means 2^30 = 0x40000000

[kikito]

You fix an existing problem (that we sometimes don't get the appropriate phase name for some phases) and I think that the change made here was as minimal as it could, which is usually good. So I am inclined to approving this.

[kikito]

(I also happen to think that the current implementation of kong/pdk/private/phases.lua is too clever and confusing - mostly because of two reasons: using a single PHASES table instead of two (one for number => name and a different one for name => number) and naming several things n (number of bits and bit being iterated over).