ash: [PARSER] Size optimisations in parameter expansion parser

ash: [PARSER] Size optimisations in parameter expansion parser

Upstream commit:

    Date: Thu, 4 Oct 2007 22:20:38 +0800
    [PARSER] Size optimisations in parameter expansion parser

    Merge flags into subtype.
    Do not write subtype out twice.
    Add likely flag on ${ vs. $NAME.
    Kill unnecessary (and bogus) PEOA check.

function                                             old     new   delta
readtoken1                                          2891    2860     -31

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>