Don't expand into (eval-when (:load-toplevel :execute) ...).

That's the implicit mode of evaluation, omitting it makes the compiler
do slightly less work.
Don't dump sanctify-for-execution into FASLs on x86oids.

It's a no-op, removing which saves 1 byte per function.
Better find-definition-sources-by-name for defstruct accessors.

Don't include source transforms for structure accessors in
sb-introspect:find-definition-sources-by-name since it doesn't provide
any useful information and only forces to select what is meant when
doing M-.