Fix the bug that build is still success when boot jars contain
non-whitelisted classes. Now, check-boot-jars.py correctly
finishes with exit code 1 when non-whitelisted classes are found.
Change-Id: Id5c80ef9fdb70213d878d569f6033be2c9eb90d3
The whitelist is a preconfigured list of regular expressions of package
names.
Run the check as a task by default in platform build.
Bug: 17434570
Change-Id: Ieaaf7efb5f4fc7a83677f3675780ca902972be97