tests: remove redundant settings of `errexit' shell flag

tests: remove redundant settings of `errexit' shell flag

* tests/aclocal-acdir.test: Do not set the `errexit' shell
flag, as it is already set by `tests/defs'.
* tests/aclocal-print-acdir.test: Likewise.
* tests/distcheck-missing-m4.test: Likewise.
* tests/distcheck-outdated-m4.test: Likewise.
* tests/java-clean.test: Likewise.
* tests/java-compile-install.test: Likewise.
* tests/java-compile-run-flat.test: Likewise.
* tests/java-compile-run-nested.test: Likewise.
* tests/java-mix.test: Likewise.
* tests/java-no-duplicate.test: Likewise.
* tests/java-nobase.test: Likewise.
* tests/java-rebuild.test: Likewise.
* tests/java-sources.test: Likewise.
* tests/java-uninstall.test: Likewise.
* tests/javaflags.test: Likewise.
* tests/nobase-nodist.test: Likewise.
* tests/py-compile-basedir.test: Likewise.
* tests/py-compile-basic.test: Likewise.
* tests/py-compile-basic2.test: Likewise.
* tests/py-compile-destdir.test: Likewise.
* tests/py-compile-env.test: Likewise.
* tests/py-compile-option-terminate.test: Likewise.
* tests/py-compile-usage.test: Likewise.  Since we are at it,
add an extra blank line, for clarity.