Revert "Short circuit fix for proposer and acceptor"

This reverts commit 986120de697e58b1f0858a02a58a54134fd90bbf.
Do not use ASan with gcc
ASan support

Now ucontext backend is forced for libcoro when ASan support is
required. Asm backend proved to have false positives, with ucontext it
looks better.

Also switched from mmap to malloc for stack allocation, which is also
ASan friendly.
Configuring ASan support in evfibers now
Added 10 minute sleep after die for ASan
Improved reporting of other values in test client
Changed separate snprintf with buffer to %.*s magic
Dropped phase 1 skip optimization

Testing with unstable network reveals that it violates protocol safety.
We need to find another ways of phase 1 optimization.