Trivial Compiler Equivalence (TCE) for mutants.

Two pieces of source are compiler-equivalent when they compile to the same BEAM code. Such a mutant can never be killed — no test can distinguish it from the original — so it is an equivalent mutant and should be dropped.

This catches cases the AST-pattern rules in Muex.Equivalence cannot, e.g. deleting a @moduledoc/@doc or any change that the compiler erases, where the resulting function bytecode is byte-for-byte identical.

The comparison is sound: both modules are compiled under the same throwaway name, disassembled, their line annotations stripped, and the remaining instruction streams compared. Equivalence is reported only on an exact match; anything that fails to compile is treated as not provably equivalent so a real mutant is never hidden.