Fix ert-tests when running compiled

Fix ert-tests when running compiled

* test/lisp/emacs-lisp/ert-tests.el (ert-test-deftest): Don't test for
specific macroexpansion, just check result of evaluation.
(ert-test-record-backtrace): Don't hardcode representation of closure in
expected backtrace, this lets the test succeed even when the test code
is compiled.

* lisp/emacs-lisp/ert.el (ert--expand-should-1): Also pass
`byte-compile-macro-environment' to `macroexpand', this allows the
`should' macro to properly handle macroexpansion of macros that were
defined in the same file when it's being compiled (Bug #17851).