Add Paxos error injections before/after save promise, proposal, decision,
paxos_response_handler, delete decision.
Adds a method to inject an error providing a lambda while avoiding to add
a continuation when the error injection is disabled.
For this provide error exception and enter() to allow flow control (i.e. return)
on simple error injections without lambdas.
Also includes Pavel's patch for CQL API for error injections, updated to
current error injection API and added one_shot support. Also added some
basic CQL API boost tests.
For CQL API there's a limitation of the current grammar not supporting
f(<terminal>) so values have to be inserted in a table until this is
resolved. See #5411
* https://github.com/alecco/scylla/tree/error_injection_v11:
paxos: fix indentation
paxos: add error injections
utils: add timeout error injection with lambda
utils: error injection add enter() for control flow
utils: error injections provide error exceptions
failure_injector: implement CQL API for failure injector class
lwt: fix disabled error injection templates
087fa42c1d