Implemented get_map_elements in HiPE

Just a simple copy-and-paste if the has_map_fields implementation, but
with an additional
     Vali := maps:get/2(...)
ICode instruction added per key-value pair.

Changed the maps_guard_fun in maps_SUITE to accept the HiPE trace
format.
Undid copy-paste code reuse by merging two help functions

 * Merged the trans_has_map_fields and trans_get_map_elements help
   functions into trans_map_query by moving the ICode assignments to
   another list, which is discarded in the has_map_fields case.
Added a get_map_elements test case to HiPE
Merge branch 'hipe-maps-get-map-elements' into hipe-maps

Added HiPE support for the get_map_elements BEAM instruction.