Optimize DefaultDeterminizeStateTable with move semantics in CompactHashBiTable.

[copybara-service]

Optimize DefaultDeterminizeStateTable with move semantics in CompactHashBiTable.

This change adds a perfect-forwarding FindId template (and a const T& overload to support initializer lists) to CompactHashBiTable, allowing entries to be efficiently copied or moved into the table. This is used in DefaultDeterminizeStateTable to avoid manual memory management and support storing std::unique_ptr<StateTuple>.

In particular:

• forcing a reference to T to allow implicit conversions (e.g. string literals to std::string).
• addressing template deduction failures for initializer lists in FindId by providing a non-template const T& overload.

Also added a new benchmark BM_DeterminizeTransHighlyNonDeterministic to stress test determinization with highly non-deterministic transducers generating long output strings.

Impact (based on fair comparison with clean config and long strings):

• Transducer determinization improved by ~9.3% (BM_DeterminizeTrans).
• On-the-fly transducer determinization improved by ~17.6% (BM_DeterminizeFstTrans).
• Acceptor determinization showed improvements of 2-3%.
• The new highly non-deterministic test is performance-neutral.
• Code cleanup: Removed manual memory management (raw pointers and manual delete) in DefaultDeterminizeStateTable to address an existing TODO.

Also:

• Fixed a potential use-after-free (null pointer dereference) in FindState where tuple->subset was accessed after tuple was moved into the state table.