pgsql: Fix ecpg tests for change that disallowed Unicode literals unless

Log Message:
-----------
Fix ecpg tests for change that disallowed Unicode literals unless
standard_conforming_strings is on.

Modified Files:
--------------
pgsql/src/interfaces/ecpg/test/expected:
preproc-strings.c (r1.2 -> r1.3)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/preproc-strings.c?r1=1.2&r2=1.3)
preproc-strings.stderr (r1.2 -> r1.3)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/preproc-strings.stderr?r1=1.2&r2=1.3)
pgsql/src/interfaces/ecpg/test/preproc:
strings.pgc (r1.1 -> r1.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/preproc/strings.pgc?r1=1.1&r2=1.2)