[Eva] Removes function [overlaps] from Ival, and inlines it in Locations.

src/kernel_services/abstract_interp/int_val.ml

src/kernel_services/abstract_interp/int_val.mli

src/kernel_services/abstract_interp/ival.ml

src/kernel_services/abstract_interp/ival.mli

src/kernel_services/abstract_interp/locations.ml