ksh does not give an error on "cd" to directories without execute bit

Issue

• ksh does not give an error on "cd" to directories without execute bit.
  See following session:

# ksh
$ pwd
/home/user001
$ ls
file01  file02
$ mkdir dir01
$ chmod 660 dir01
$ cd dir01
$ pwd
/home/user001/dir01
$ ls 
dir01  file01  file02
$ ll
total 4
drw-rw----. 2 user001 user001 4096 May 29 19:44 dir01
-rw-rw-r--. 1 user001 user001    0 May 29 19:43 file01
-rw-rw-r--. 1 user001 user001    0 May 29 19:43 file02