Drop the inline definition of the TEST_WITH macro in favor of using a
verbatim copy of the file that contains the macro from the dovecot/core
project. This allows easier tracking of changes to the macro that happen
upstream.

Copied verbatim from dovecot/core project.

Copied verbatim from dovecot/core project.

Added --disable-shared to DISTCHECK_CONFIGURE_FLAGS (in dovecot.m4) to prevent libtool from relinking the libraries.