xgettext: Simplify calling convention of arglist_parser_remember.

xgettext: Simplify calling convention of arglist_parser_remember.

* gettext-tools/src/xg-arglist-parser.h (struct partial_call): Add
'msgid_comment_is_utf8' field.
(arglist_parser_remember): Add comment_is_utf8 argument.
* gettext-tools/src/xg-arglist-parser.c (arglist_parser_alloc,
arglist_parser_clone): Update.
(arglist_parser_remember): Add comment_is_utf8 argument.
(arglist_parser_done): Pass comment_is_utf8 value down to remember_a_message.
* gettext-tools/src/x-c.c (extract_parenthesized): Update callers. Don't set
xgettext_current_source_encoding around arglist_parser_remember calls.
* gettext-tools/src/x-csharp.c (extract_parenthesized): Likewise.
* gettext-tools/src/x-java.c (extract_parenthesized): Likewise.
* gettext-tools/src/x-javascript.c (extract_balanced): Likewise.
* gettext-tools/src/x-perl.c (extract_balanced): Likewise.
* gettext-tools/src/x-python.c (extract_balanced): Likewise.
* gettext-tools/src/x-vala.c (extract_balanced): Likewise.
* gettext-tools/src/x-awk.c (extract_parenthesized): Update callers.
* gettext-tools/src/x-elisp.c (read_object): Likewise.
* gettext-tools/src/x-librep.c (read_object): Likewise.
* gettext-tools/src/x-lisp.c (read_object): Likewise.
* gettext-tools/src/x-lua.c (extract_balanced): Likewise.
* gettext-tools/src/x-php.c (extract_balanced): Likewise.
* gettext-tools/src/x-scheme.c (read_object): Likewise.
* gettext-tools/src/x-sh.c (read_command): Likewise.
* gettext-tools/src/x-tcl.c (read_command): Likewise.