Override log_error_verbosity to "default" in test 009_log_temp_files

Per report from buildfarm member prion.  The CI does not use this
parameter, and this buildfarm member sets log_error_verbosity to
"verbose".  This would generate extra LOCATION entries in the logs,
causing the regexps of the test to fail.

Trying to support log_error_verbosity=verbose in the test would mean to
tweak all the regexps used in the test to detect an optional set of
LOCATION lines, at least.  This would not improve the coverage, and
forcing the GUC value is simpler.

Oversight in 76bba03312.

Discussion: https://postgr.es/m/aPBaNNGiYT3xMBN1@paquier.xyz

src/test/modules/test_misc/t/009_log_temp_files.pl

@@ -18,6 +18,7 @@ $node->append_conf(
 work_mem = 64kB
 log_temp_files = 0
 debug_parallel_query = off
+log_error_verbosity = default
 ));
 $node->start;