#9286: Fix the rfc822 parser to preserve whitespace in address local part.

#9286: Fix the rfc822 parser to preserve whitespace in address local part.

Such addresses are not RFC compliant except under the 'obsolete syntax'
rules, but before this fix the whitespace was dropped from the input,
concatenating the pieces.  That breaks one of the principles of the
email package, that of preserving the input as much as possible.
It also denies the application program the opportunity to apply its
own heuristics to interpretation of such non-compliant addresses.

It is possible users of the email package were depending on the local
part always being a single token, so this fix will not be backported.