Aconfig: sort the parsed flag order in create-cache

This change will sorted the parsed flags from the declarations. Without
this change the code will expect the passed in declarations sorted.
After this change the code will still guarantee the parsed flags in the
cache is sorted, but it won't expect the passed in declarations are
sorted

Test: atest aconfig.test
Bug: 291926035
Change-Id: I5f0637fe770003224b128591890e04277bc09345