Remove some explicit runtime loads of pcase

Remove some explicit runtime loads of pcase

Pcase is macros, so these should have used eval-when-compile.
Anyway, pcase entry points are autoloaded, so the compiler handles it.
* lisp/profiler.el, lisp/emacs-lisp/eieio-core.el:
* lisp/emacs-lisp/generator.el, lisp/emacs-lisp/subr-x.el:
* lisp/progmodes/xref.el: No need to require pcase.