install tests and functions to run them * configure.ac (octtestsdir): New variable. * build-aux/common.mk (octtestsdir): New variable. (do_subst_default_vals): Substitute it. (test-file-commands): New macro. (%.cc-tst:%.cc, %.yy-tst:%.yy, %.ll-tst:%.ll): New rules. * libinterp/Makefile.am (TST_FILES_SRC, TST_FILES, libinterptestsdir, nobase_libinterptests_DATA): New variables. * defaults.in.h (OCTAVE_OCTTESTSDIR): New macro. * liboctave/Makefile.am (LIBOCTAVE_TST_SRC, TST_FILES_SRC, TST_FILES, liboctavetestsdir, nobase_liboctavetests_DATA): New variables. * toplev.cc (Foctave_config_info): Include octtestsdir in the struct. * fntests.m: Look in topbuilddir for C++ test files. * __run_test_suite__.m: New function, extracted from test/fntests.m. Look for -tst files, not .cc files. Don't report -tst files that are missing tests (there won't be any). * __prog_output_assert__.m, __printf_assert__.m: New functions, extracted from __run_test_suite__.m and renamed from prog_output_assert and printf_assert. Change all uses. * scripts/testfun/module.mk (testfun_FCN_FILES): Include new files in the list. * test/Makefile.am (GENERATED_BC_OVERLOADS_DIRS, GENERATED_BC_OVERLOADS_FILES, fixedtestsdir, nobase_fixedtests_DATA): New variables. (CLEANFILES): Include $(GENERATED_BC_OVERRLOADS_FILES) in the list. (clean-local): Use $(GENERATED_BC_OVERLOADS_DIRS). * build_bc_overload_tests.sh: New options, --list-files, --list-dirs, and --list-classes. * test/classes/module.mk (classes_FCN_FILES): Include recently added .m files in the list. * test.m: Use "var" argument for exist in tests.