tests: fix usdt/tst.dlclose1.sh

This test fails purely because of a bufsize expansion message, since in
v2 the bufsize must be at least one page.

Boost the bufsize in the test to the largest likely page size (64KiB,
seen on AArch64) to quash the message.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>

test/unittest/usdt/tst.dlclose1.sh

@@ -1,14 +1,12 @@
 #!/bin/bash
 #
 # Oracle Linux DTrace.
-# Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
 # Licensed under the Universal Permissive License v 1.0 as shown at
 # http://oss.oracle.com/licenses/upl.
 #
 # This test verifies that USDT providers are removed when its associated
 # load object is closed via dlclose(3dl).
-#
-# @@xfail: dtv2
 
 PATH=/usr/bin:/usr/sbin:$PATH
 
@@ -115,7 +113,7 @@ if [ $? -ne 0 ]; then
 fi
 
 script() {
-	$dtrace -Zw -x bufsize=1k -c ./main -qs /dev/stdin <<EOF
+	$dtrace -Zw -x bufsize=64k -c ./main -qs /dev/stdin <<EOF
 	syscall::pause:entry,
 	syscall::rt_sig*:entry
 	/pid == \$target/