tests: Accommodate a shell that is not in /bin/sh. * tests/init.sh (setup_): Set srcdir and builddir. (BOURNE_SHELL): New variable. * modules/acl-tests (Depends-on): Add 'test-framework-sh'. * modules/file-has-acl-tests (Depends-on): Likewise. * modules/copy-file-tests (Depends-on): Likewise. * tests/test-set-mode-acl-1.sh: Use the test framework. Invoke shell scripts through $BOURNE_SHELL. * tests/test-set-mode-acl-2.sh: Likewise. * tests/test-copy-acl-1.sh: Likewise. * tests/test-copy-acl-2.sh: Likewise. * tests/test-file-has-acl-1.sh: Likewise. * tests/test-file-has-acl-2.sh: Likewise. * tests/test-copy-file-1.sh: Likewise. * tests/test-copy-file-2.sh: Likewise. * tests/test-set-mode-acl.sh (builddir): Consider value set by the invoker. * tests/test-copy-acl.sh (builddir): Likewise. * tests/test-file-has-acl.sh (builddir): Likewise. * tests/test-copy-file.sh (builddir): Likewise. * tests/test-vc-list-files-cvs.sh: Don't create shims for executables in build-aux/. Instead, invoke shell scripts through $BOURNE_SHELL. * tests/test-vc-list-files-git.sh: Likewise.