Fix bugs related with double-sided communications

Description

Fix bugs related with double-sided communications for hybrid functionals, causing for instance a segfault for HSE06 in solids without k-point symmetries.

More precisely, this fixes:

• the energy that was not correct
• the indices that got broken

Tests are added to cover the failing test and possible catch extra problems.

Closes #1239 (closed)

News snippet

Fix bugs related with double-sided communications for hybrid functionals, causing for instance a segfault for HSE06 in solids without k-point symmetries.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.