Revert "Develop tests for issues #5866 and #8858"

This reverts commit 693c1fc478.  This
change resulted in a kmem leak being observed in existing code which
needs to be identified and addressed.

Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #8978
Closes #9090

tests/zfs-tests/cmd/Makefile.am

@@ -19,7 +19,6 @@ SUBDIRS = \
 	mmap_libaio \
 	mmapwrite \
 	nvlist_to_lua \
-	online_recv \
 	randfree_file \
 	randwritecomp \
 	readmmap \

tests/zfs-tests/cmd/online_recv/.gitignore

@@ -1 +0,0 @@
-/online_recv

tests/zfs-tests/cmd/online_recv/Makefile.am

@@ -1,15 +0,0 @@
-include $(top_srcdir)/config/Rules.am
-
-pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/bin
-
-DEFAULT_INCLUDES += \
-	-I$(top_srcdir)/include \
-	-I$(top_srcdir)/lib/libspl/include
-
-pkgexec_PROGRAMS = online_recv
-
-online_recv_SOURCES = online_recv.c
-online_recv_LDADD = \
-	$(top_builddir)/lib/libspl/libspl.la \
-	$(top_builddir)/lib/libnvpair/libnvpair.la \
-	$(top_builddir)/lib/libzfs_core/libzfs_core.la

tests/zfs-tests/cmd/online_recv/online_recv.c

@@ -1,52 +0,0 @@
-/*
- * CDDL HEADER START
- *
- * This file and its contents are supplied under the terms of the
- * Common Development and Distribution License ("CDDL"), version 1.0.
- * You may only use this file in accordance with the terms of version
- * 1.0 of the CDDL.
- *
- * A full copy of the text of the CDDL should have accompanied this
- * source.  A copy of the CDDL is also available via the Internet at
- * http://www.illumos.org/license/CDDL.
- *
- * CDDL HEADER END
- */
-
-/*
- * Copyright (c) 2019 by Datto, Inc. All rights reserved.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <libzfs_core.h>
-
-int zfs_fd;
-
-/*
- * Use libzfs_core to do a "zfs receive".  This allows us to
- * bypass certain checks in the zfs command utility and
- * perform an online receive into an existing filesystem for
- * testing purposes.
- */
-int
-main(int argc, const char *argv[])
-{
-	int err = 0;
-
-	if (argc < 2) {
-		fprintf(stderr, "usage: online_recv <destination>\n");
-		exit(2);
-	}
-
-	(void) libzfs_core_init();
-
-	err = lzc_receive(argv[1], NULL, NULL, B_TRUE, B_FALSE, 0);
-
-	libzfs_core_fini();
-
-	return (err);
-}