Function projection1_source_real_fast_on_vm 

pub fn projection1_source_real_fast_on_vm(
    core_types: &str,
    _interpreter: &str,
    program: &str,
) -> Result<String, String>

VM-driven twin of projection1_source_real_fast.

Executes the identical assembled PE program on the register bytecode VM (vm_run_source) instead of the tree-walker. The PE engine is a fixed program — only its encodedMain input varies per call — so the VM either supports the whole engine or none of it; measured ~2× faster than the tree-walker with a byte-identical residual. The corpus-wide equivalence is locked by futamura_tier_lock.