maintcheck: fix more maintainer-check failures

maintcheck: fix more maintainer-check failures

* tests/test-driver-custom-no-html.test (no-rst): Use `EOF',
not `EoL', as the here-document delimiter.
* tests/test-trs-basic.test: Use `cat + here-doc' rather
than `echo' when creating the dummy test scripts, to please
maintainer-check.
* tests/test-trs-recover.test: Use creative quoting where
needed, to please maintainer-check.
* tests/parallel-tests-no-color-in-log.test: Likewise.
* tests/parallel-tests-dry-run.test: Likewise.