Silence some byte-compiler warnings in tests

Silence some byte-compiler warnings in tests

* test/lisp/emacs-lisp/cl-generic-tests.el:
* test/lisp/progmodes/elisp-mode-tests.el: Declare functions
referred to within macroexpansions.
(xref-elisp-overloadable-no-default)
(xref-elisp-overloadable-co-located-default)
(xref-elisp-overloadable-separate-default): Prefix unused arguments
with underscore.

* test/lisp/international/ccl-tests.el:
* test/lisp/wdired-tests.el:
* test/lisp/emacs-lisp/package-tests.el: Declare functions used.
(package-test-update-archives, package-test-signed): Use
revert-buffer in place of its obsolete alias package-menu-refresh.

* test/lisp/eshell/eshell-tests.el:
* test/lisp/mail/footnote-tests.el:
* test/src/buffer-tests.el: Require dependencies used.

* test/lisp/image/exif-tests.el: Remove unneeded (require 'seq).
(test-exit-direct-ascii-value): Actually perform the test.
* test/lisp/progmodes/sql-tests.el (sql-test-add-existing-product):
Fix typo.

* test/lisp/simple-tests.el (with-shell-command-dont-erase-buffer):
* test/src/data-tests.el (test-bool-vector-bv-from-hex-string)
(test-bool-vector-apply-mock-op): Remove unused local variables.