Specifically, this commit makes the `-c`/`--section` parameter
strictly ordered and hierarchical, unlike how it behaved before,
which was a huge mess -- see #3038 for details.

Closes #3038

This commit causes small (~5%) slowdown when processing strings
that consist mostly of escaped characters, but improves throughput
by about 100% for strings that consist mostly of characters that
do not need escaping.

Forbid deducing reference types for m_predicate in FilterGenerator to prevent dangling references.
This is needed for out-of-line predicates to work correctly instead of undefined behavior or crashes.

---------

Co-authored-by: Tek Mate <mate.tek@evosoft.com>

As with the JSON writer, the old code was made to be simple and
for each char just decided whether it needs escaping, or should be
written as-is. The new code instead looks for characters that need
escaping and batches writes of characters that do not.

This provides 4-8x speedup (length dependent) for writing strings
that do not need escaping, and keeps roughly the same performance
for those that do need escaping.

The old code was exceedingly simple, as it went char-by-char and
decided whether to write it to the output stream as-is, or escaped.
This caused a _lot_ of stream writes of individual characters.

The new code instead looks for characters that need escaping, and
bulk-writes the non-escaped characters in between them. This leads
to about the same performance for strings that comprise of only
escaped characters, and 3-10x improvement for strings without any
escaping needed.

In practice, we should expect the former rather than the latter,
but this is still nice improvement.

This stops tests failing falsely if the assertion passed, but the
stringification itself failed as the assertion was sent to the reporter.

I don't think that stringification should be fallible, but the
overhead in compilation ended up being small enough (<0.5% on `SelfTest`)
that it might be worth implementing, in case there is more users
with weird `StringMaker`s than just MongoDB.

Closes #2980

Fixes #2685