Don't use java.util.regex for two simple wildcard cases

Don't use java.util.regex for two simple wildcard cases

To improve ignore parser performance we can avoid using java.util.regex
code on simple wildcard patterns with leading or trailing asterisk. As
those patterns represent a majority of ignore rules, the index diff
performance can be drastically increased on huge repository with lot of
ignore rules.

Bug: 450466
Change-Id: I80428441cc8d5de5468813f841d89322413eed8b
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>