message: Fix regression that omitted -DNDEBUG in opt builds after toolchain refactoring.
  Not adding -DNDEBUG leads to enabling assertions which makes LLVM often 10x slower.
diff: @@ -583,7 +583,11 @@ def _features(cpu, compiler, ctx):
  ),
  ],
  ),
  - feature(name = "opt"),
  + feature(name = "disable-assertions"),
  + feature(
  + name = "opt",
  + implies = ["disable-assertions"],
  + ),
  feature(name = "fastbuild"),
  feature(name = "dbg"),
  feature(name = "supports_dynamic_linker", enabled = True),
  