remove @call-with-current-continuation memoizer

remove @call-with-current-continuation memoizer

* module/ice-9/boot-9.scm (call-with-current-continuation): Change to
  primcall call-with-current-continuation.

* libguile/memoize.h:
* libguile/expand.c (scm_sym_atcall_cc): Remove.

* libguile/memoize.c (memoize): Memoize call/cc primcalls to
  SCM_M_CONT.
  (m_call_cc): Remove.
  (unmemoize): Unmemoize to call-with-current-continuation.

* module/language/tree-il/compile-glil.scm (flatten-lambda-case): Update
  to call-with-current-continuation without @ prefix, and fix fallback
  case.

* module/language/tree-il/primitives.scm (*multiply-valued-primitives*):
  (*interesting-primitive-names*): Remove
  @call-with-current-continuation.
  (call/cc): Expand to call-with-current-continuation.

* test-suite/tests/tree-il.test ("call/cc"): Update to use and expect
  call-with-current-continuation primcalls / toplevel refs.