Fixlets for internationalization tests.

Fixlets for internationalization tests.

* tests/pot-copyright.test: Add trailing `:' command.
* tests/pot-empty.test: Likewise.
* tests/pot-download1.test: Likewise.  Use `Exit', not `exit'.
($required): Remove gzip, as we must take it for granted anyway.
* tests/pot-format-qt1.test: Use `Exit', not `exit'.  Use `$MAKE',
not bare `make'.  Add trailing `:' command.  Avoid useless use of
cat.  Do not redirect output of grep, cmp, etc. to /dev/null.
Other minor cosmetic changes.
* tests/pot-format-java1.test: Likewise, and ...
($required): Remove gzip, as we must take it for granted anyway.
* tests/pot-format-java2.test: Likewise.
* tests/pot-format-tcl1.test: Likewise.
* tests/pot-linguas.test: Likewise.
* tests/pot-noinst.test: Likewise.
* tests/pot-samedir.test: Likewise.
* tests/pot-topsrcdir.test: Likewise.
* tests/pot-format-csharp1.test: Likewise, and quote all literal
dots in grep regexps.
* tests/pot-enable1.test: Use `$MAKE', not bare `make'.  Do not
redirect grep output to /dev/null.  Add trailing `:' command.
(Makefile.am): Explicitly declare phony target as such.
* tests/pot-enable2.test: Likewise.
* tests/pot-msgidbugs.test: Use `$MAKE', not bare `make'.  Avoid
useless use of cat.  Add trailing `:' command.
* tests/pot-xgettext1.test: Likewise.
* tests/pot-xgettext2.test: Likewise.
* tests/pot-xgettext3.test: Likewise.
* tests/pot-xgettext4.test: Likewise.
* tests/pot-no-linguas.test: Likewise, and do not redirect grep
output to /dev/null.
* tests/pot-override1.test: Likewise.
* tests/pot-macro-warn.test: Avoid useless use of `AUTOMAKE_run'.
Add trailing `:' command.
* tests/pot-warn1.test: Likewise.
* tests/pot-warn2.test: Likewise.