roachtest: sqlsmith/setup=empty/setting=no-mutations failed

[cockroach-teamcity]

(roachtest).sqlsmith/setup=empty/setting=no-mutations failed on provisional_202007081918_v20.2.0-alpha.2@cf051c8c91d5e1d5196e6d2fdc9382364e1d44e8:

The test failed on branch=provisional_202007081918_v20.2.0-alpha.2, cloud=gce:
test artifacts and logs in: /home/agent/work/.go/src/github.com/cockroachdb/cockroach/artifacts/sqlsmith/setup=empty/setting=no-mutations/run_1
	sqlsmith.go:169,sqlsmith.go:199,test_runner.go:757: error: pq: internal error: inconsistent Case return types bool unknown
		stmt:
		SELECT
			tab_22750.col_39308 AS col_39309
		FROM
			(VALUES (4265946213:::OID), (1469056602:::OID), (684942977:::OID), (2684856553:::OID)) AS tab_22750 (col_39308)
		WHERE
			NULL
		GROUP BY
			tab_22750.col_39308
		HAVING
			st_dwithin('0101000020E6100000000000000000F03F000000000000F03F':::GEOGRAPHY::GEOGRAPHY, '0101000020E6100000000000000000F03F000000000000F03F':::GEOGRAPHY::GEOGRAPHY, (-0.00021452126788878978):::FLOAT8::FLOAT8, CASE WHEN crdb_internal.is_admin()::BOOL THEN true ELSE (true AND NULL) END::BOOL)::BOOL
		LIMIT
			80:::INT8;

More

Artifacts: /sqlsmith/setup=empty/setting=no-mutations

See this test on roachdash
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[yuzefovich]

dup of #51099