remove empty '' in ${var@Q} result?

[Clark Wang]

See following example:

[STEP 100] # echo $BASH_VERSION
4.4.12(2)-release
[STEP 101] # v=\'\'
[STEP 102] # printf '%q\n' "$v"
\'\'
[STEP 103] # printf '%s\n' "${v@Q}"
''\'''\'''
[STEP 104] #