Compile some standalone tests to bytecode

* test-suite/standalone/test-out-of-memory:
* test-suite/standalone/test-stack-overflow: Compile these files before
  running them.  That way, recursion can check the stack-overflow
  mechanism instead of the memory allocation mechanism.  We compile
  beforehand as a prepass so as not to impose an rlimit on a Guile that
  previously ran auto-compilation.
New pass to avoid free variable creation for self-recursion

* module/language/cps/self-references.scm: New pass, avoids the need for
  self-recursion to allocate free variables.

* module/Makefile.am:
* module/language/cps/compile-bytecode.scm: Wire up the new pass.
Remove obsolete comment in compile-bytecode.scm

* module/language/cps/compile-bytecode.scm (optimize): Remove an
  obsolete comment.