TESTS: Flag a whole bunch of tests as not supported on non-iSCSI backends

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>

test-tool/test_write12_residuals.c

@@ -43,6 +43,14 @@ test_write12_residuals(void)
 	CHECK_FOR_DATALOSS;
 	CHECK_FOR_SBC;
 
+	if (sd->iscsi_ctx == NULL) {
+		const char *err = "[SKIPPED] This WRITE12 test is only "
+			"supported for iSCSI backends";
+		logging(LOG_NORMAL, "%s", err);
+		CU_PASS(err);
+		return;
+	}
+
 	/* Try a write12 of 1 block but xferlength == 0 */
 	task = malloc(sizeof(struct scsi_task));
 	CU_ASSERT_PTR_NOT_NULL(task);