54674: ::= didn't respect parameter flags

The documentation says
    ${name::=word}
          In  the first form, if name is unset then set it to word; in
          the second form, if name is unset or null then set it to word;
          and in the third form, unconditionally  set name to word.  In
          all forms, the value of the parameter is then substituted.

Particularly that "the value of the parameter is substituted", not "the
word is substituted".

This is what happens before the fix, and similarly for array flags like "unique":

% typeset -E3 fl; hi=5; echo ${fl::=hi}
hi
% echo $fl
5.00e+00

0 files changed, 0 insertions, 0 deletions