Added $(TESTS_SHELL) at end of TESTS_ENVIRONMENT.  This lets the user run the tests using a shell other than the default /bin/sh by using, e.g., make check TESTS_SHELL=/bin/bash.  Thanks to Tom Lane <tgl@sss.pgh.pa.us> for suggesting this.
Added $(TESTS_SHELL) at end of TESTS_ENVIRONMENT.  This lets the
user run the tests using a shell other than the default /bin/sh
by using, e.g., make check TESTS_SHELL=/bin/bash.  Thanks to
Tom Lane <tgl@sss.pgh.pa.us> for suggesting this.

dscho/nmh,dscho/nmh,dscho/nmh,mcr/nmh,dscho/nmh,mcr/nmh