Code review request: 7063647, jsse/runtime, To use synchronized map in key manager

[Xuelei Fan]

webrev: http://cr.openjdk.java.net/~xuelei/7063647/webrev.00/

SunX509KeyManagerImpl should be multiple thread safe, need to
synchronize cached map:
    private Map<String,X509Credentials> credentialsMap;
    private Map<String,String[]> serverAliasCache;

Thanks,
Xuelei