Default to using specialized implementation for some builtins.

Applies to !/@not_strictly_false/==/!=/@in.

This avoids some of the overhead for function dispatch at the cost of duplicating a subset of that logic and restricting the ability to customize them.

Note: the fast builtins assume heterogeneous equality behavior. If not enabled, the runtime will fall back to the provided equals functions, instead of the new builtins step.
PiperOrigin-RevId: 717979767

Author: jnthntatum

eval/public/cel_options.h

@@ -195,7 +195,7 @@ struct InterpreterOptions {
   // if they exist.
   //
   // Currently applies to !_, @not_strictly_false, _==_, _!=_, @in
-  bool enable_fast_builtins = false;
+  bool enable_fast_builtins = true;
 };
 // LINT.ThenChange(//depot/google3/runtime/runtime_options.h)
 

runtime/runtime_options.h

@@ -165,7 +165,7 @@ struct RuntimeOptions {
   // if they exist.
   //
   // Currently applies to !_, @not_strictly_false, _==_, _!=_, @in
-  bool enable_fast_builtins = false;
+  bool enable_fast_builtins = true;
 };
 // LINT.ThenChange(//depot/google3/eval/public/cel_options.h)