Fix regression in POSIX mode behavior

Commit 235a85657 introduced a regression in evaluation of POSIX modes
that require group DENY entries in the internal ZFS ACL. An example
of such a POSX mode is 007. When write_implies_delete_child is set,
then ACE_WRITE_DATA is added to `wanted_dirperms` in prior to calling
zfs_zaccess_common(). This occurs is zfs_zaccess_delete().

Unfortunately, when zfs_zaccess_aces_check hits this particular DENY
ACE, zfs_groupmember() is checked to determine whether access should be
denied, and since zfs_groupmember() always returns B_TRUE on Linux and
so this check is failed, resulting ultimately in EPERM being returned.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Andrew Walker <awalker@ixsystems.com>
Closes #11760

tests/runfiles/common.run

@@ -28,6 +28,10 @@ failsafe = callbacks/zfs_failsafe
 outputdir = /var/tmp/test_results
 tags = ['functional']
 
+[tests/functional/acl/off]
+tests = ['posixmode']
+tags = ['functional', 'acl']
+
 [tests/functional/alloc_class]
 tests = ['alloc_class_001_pos', 'alloc_class_002_neg', 'alloc_class_003_pos',
     'alloc_class_004_pos', 'alloc_class_005_pos', 'alloc_class_006_pos',

tests/runfiles/sanity.run

@@ -30,6 +30,10 @@ failsafe = callbacks/zfs_failsafe
 outputdir = /var/tmp/test_results
 tags = ['functional']
 
+[tests/functional/acl/off]
+tests = ['posixmode']
+tags = ['functional', 'acl']
+
 [tests/functional/alloc_class]
 tests = ['alloc_class_003_pos', 'alloc_class_004_pos', 'alloc_class_005_pos',
     'alloc_class_006_pos', 'alloc_class_008_pos', 'alloc_class_010_pos',