Description of problem:
`zsh` behavior changed after the following bugfix:
Bug 1399534 - zsh heredoc crash (zsh-5.0.2-25.el7_3.1)

Version-Release number of selected component (if applicable):
zsh-5.0.2-25.el7_3.1

How reproducible:
After updating of `zsh` package it started to fail with "name:#: parse error" caused by `BLDARC` followed by other character(s).

Steps to Reproduce:
Customer installed the updated package and got the following error - 'parse error':
---------------------------------------------------
[root@fastvm-r7-3-73 ~]# rpm -q zsh
zsh-5.0.2-25.el7_3.1.x86_64
[root@fastvm-r7-3-73 ~]# cat -n try2
     1	cat >> /tmp/try <<EOF
     2	# Begin code generated from ${script} -----
     3	export A="$(tr '\n' ' ' <<BLDARC
     4	content
     5	BLDARC)"
     6	EOF
[root@fastvm-r7-3-73 ~]# zsh try2
try2:7: parse error
---------------------------------------------------

but script was working on (zsh-5.0.2-7.el7.x86_64):
--------------------------------------------------
[root@fastvm-r7-3-73 ~]# rpm -q zsh
zsh-5.0.2-7.el7.x86_64
[root@fastvm-r7-3-73 ~]# cat -n try2
     1	cat >> /tmp/try <<EOF
     2	# Begin code generated from ${script} -----
     3	export A="$(tr '\n' ' ' <<BLDARC
     4	content
     5	BLDARC)"
     6	EOF
[root@fastvm-r7-3-73 ~]# zsh try2
[root@fastvm-r7-3-73 ~]# cat /tmp/try 
# Begin code generated from  -----
export A="content "
---------------------------------------------------


Actual results:
> try2:7: parse error

Expected results:
> executed successfully


Additional info:
BZ# References:
Bug 1399534 - zsh heredoc crash (7.3.z : ERRATA CLOSED)
Bug 1374752 - zsh heredoc crash (7.4.0 : ... )