[PGPRO-5703] Run installcheck against an existing installation.

Tags: pg_query_state

Author: antamel

Makefile

@@ -30,7 +30,11 @@ ISOLATIONCHECKS = corner_cases
 
 check: isolationcheck
 
-installcheck: isolationcheck
+installcheck: submake-isolation
+	$(MKDIR_P) isolation_output
+	$(pg_isolation_regress_installcheck) \
+	  --outputdir=isolation_output \
+	$(ISOLATIONCHECKS)
 
 isolationcheck: | submake-isolation temp-install
 	$(MKDIR_P) isolation_output