RFR(S): 8246308: Reference count for PackageEntry::name may be incorrectly decremented

[Calvin Cheung]

JBS: https://bugs.openjdk.java.net/browse/JDK-8246308

webrev: http://cr.openjdk.java.net/~ccheung/jdk16/8246308/webrev.00/

Please refer to the bug report for a description of the problem.
The proposed change also fixes a similar problem in 
systemDictionaryShared.cpp.

Passed tier1,2 tests.

thanks,

Calvin