All local connection timeout settings not related to the testing
scenario are removed within this change. Instead of removed values
the default one from src/box/lua/load_cfg.lua will be used.
The approach with a single default value helps to avoid flaky test
results regarding different timeout values and makes the future
maintainence easier.

The change is required for LSAN and ASAN testing machinery since it
introduces a little overhead and cause failures for tests with
excessively strict time limits.

Needed for #2058