test-json-parser: Fixed failing test with some non-gcc/clang compilers.
test-json-parser: Fixed failing test with some non-gcc/clang compilers.

jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch