RFR 8170870: Fix synchronization of access to PackageEntryTables and ModuleEntryTables

[harold seigel]

Hi,

Please review this fix for bug JDK-8170870.  The fix adds a missing 
load_ptr_acquire and fixes some asserts.  It also removes the 
exported_pending_delete array, improving the management of package 
qualified export lists.

Open Webrev: 
http://cr.openjdk.java.net/~hseigel/bug_8170870/webrev/index.html

JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8170870

The fix was tested with the JCK Lang and vm tests, the JTreg hotspot, 
java/io, java/lang, java/util and other JTReg tests, and the NSK 
co-located and non-colocated tests.

Thanks, Harold