It tested the installed binaries. This fixes 9.6 and 9.5 to follow
later versions and "make -C src/test/isolation check" in this respect.
./pg_isolation_regress --bindir='$(bindir)' $(EXTRA_REGRESS_OPTS) --inputdir=$(srcdir) --schedule=$(srcdir)/isolation_schedule prepared-transactions
check-prepared-txns: all temp-install
- ./pg_isolation_regress --temp-instance=./tmp_check $(TEMP_CONF) $(EXTRA_REGRESS_OPTS) --inputdir=$(srcdir) --schedule=$(srcdir)/isolation_schedule prepared-transactions
+ $(with_temp_install) ./pg_isolation_regress --temp-instance=./tmp_check $(TEMP_CONF) --inputdir=$(srcdir) --bindir= $(EXTRA_REGRESS_OPTS) --schedule=$(srcdir)/isolation_schedule prepared-transactions