Fix interpolation in test name.

A pre-commit review had reported the problem, but the fix reached only
v10 and earlier.  Back-patch to v11.

Discussion: https://postgr.es/m/20200423.140546.1055476118690602079.horikyota.ntt@gmail.com

Author: nmisch

src/test/recovery/t/020_archive_status.pl

@@ -64,7 +64,7 @@
 		FROM pg_stat_archiver
 	}),
 	"0|$segment_name_1",
-	'pg_stat_archiver failed to archive $segment_name_1');
+	"pg_stat_archiver failed to archive $segment_name_1");
 
 # Crash the cluster for the next test in charge of checking that non-archived
 # WAL segments are not removed.