RFR: 8154283: Check for clash between package and class not working when package in a different module

[Jan Lahoda]

Hi,

Please review the following fix. When checking for package-class clash, 
all packages visible from the given module should be checked, not only 
packages in the given module. Also, cleaning up a forgotten related 
field in MemberEnter.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8154283

Webrev:
http://cr.openjdk.java.net/~jlahoda/8154283/webrev.00/

Thanks,
    Jan