Revert "maybe I'm doing the wrong thing by adding use lines for test modules"
Wow.  Even with the "fix" in, it runs correctly once, and then starts vomiting
with a similar error again as before the fix.  it'll fail 20 times in a
row, then pass 20 times in a row.  there's some haunted house level
shit going wrong here.

This reverts commit b121a061d8f220dc6c842ea187c12a199526333a.
Revert "was barfing with "Can't locate object method "new" via package "MyElement" (perhaps you forgot to load "MyElement"?) at lib/SOAP/WSDL/XSD/Typelib/Comple"
ref haunted house level shit going weird message in previous revert.

This reverts commit d221e87b29327b1dde045b5e4779358d218447b9.
Huh.  Between 5.12 and 5.16 somewhere, the behavior of ClassName->isa('UNIVERSAL') changed.
It used to be that that would return true if and only if that namespace existed.
Now it always returns true for any random non-existant made up name.
Changed this to do ->can() on a known existing method modules with this API have (serialize)
instead after floundering around for a bit.  exists ${"main::"}{$type.'::'} worked a little
bit but made it barf for some reason I didn't investigate.
This is the problem apparently behind the previous "haunted house level shit" fixes and
reversions.  This thing does automatically load these modules on the fly.  Would be nice
if the unit tests had some comments in them.