Reassociate erc-networks--id for orphaned queries

Reassociate erc-networks--id for orphaned queries

* lisp/erc/erc-networks.el (erc-networks--examine-targets): Adopt the
server's network ID in query buffers created before MOTD's end.  Do
this to avoid a type error in the process filter when renaming
buffers.
* lisp/erc/erc-networks.el (erc-networks--examine-targets): New test.
* test/lisp/erc/erc-scenarios-base-upstream-recon-znc.el
(erc-scenarios-upstream-recon--znc/severed): New test.
* test/lisp/erc/erc-scenarios-misc.el
(erc-scenarios-base-mask-target-routing): Adjust timeout.
* test/lisp/erc/resources/base/upstream-reconnect/znc-severed.eld:
New file.
* test/lisp/erc/resources/erc-tests-common.el
(erc-tests-common-make-server-buf): Use NAME parameter for creating
ID.