Disable gencgc wipe feature on account of lp#1389866
more appropriate type cache sizes

Also use type-list-cache-hash in place of sxhash in two places, rather
improving the cache utilization
no more DEFINE-CACHED-SYNONYM

its two users, MAKE-ARRAY-TYPE and MAKE-UNION-TYPE (why?) are not
called all that often, at least during a full build, and the use of
SXHASH as the hash function led to huge numbers of collisions.  Rather
than try to invent a useful hash function for these constructors,
simply don't cache them.  That allows us to delete
DEFINE-CACHED-SYNONYM, too.
more deterministic xc-host version of VALUES-SPECIFIER-TYPE

now that VALUES-SPECIFIER-TYPE is the only cached function which
accepts arbitrary lisp objects (and uses SXHASH), make an xc-host
version of it which simply uses an EQUAL hash table, and stores
everything during the XC build.  Strictly speaking this is not quite
correct, because of the theoretical possibility of multiple types
like (MEMBER #1=(FOO)) (MEMBER #2=(FOO)), but this is pretty unlikely
to happen.

I would have liked to write

  (macrolet ((values-specifier-type-body ...))
    #+sb-xc-host (let ((table (make-hash-table))) (defun ...))
    #-sb-xc-host (define-cached ...))

but that breaks during cross-compilation when one of the DEFINE-CACHED
components complains about not being able to be inlined on the grounds
that the lexical environment is too hairy.  Oh well.
reproducible build!

make ctype cacheing deterministic:

* generate ctype hash codes using a LCG under the build's control, not
  the host implementation's RANDOM
* deterministically use the first of the two hash values to evict from
  the cache in case of a collision

All xc lisp-obj files are bitwise identical, with ccl{32,64} and
clisp, building for x86-64/linux with default features.