RFR: 8024009 : Remove jdk.map.useRandomSeed system property

[Brent Christian]

Please review my fix to remove the jdk.map.useRandomSeed system property 
added earlier in jdk8.

Some history is in the bug report,
http://bugs.sun.com/view_bug.do?bug_id=8024009

HashMap and LinkedHashMap stopped using the random hash seed as of
8023463.  This change removes the code to read the jdk.map.useRandomSeed 
property and setup the hashSeed in Hashtable and WeakHashMap.

Hashtable got a couple extra things cleaned up:
* hash() calls were converted back to key.hashCode(), returning the code 
to its state prior to 7126277 (alternative String hashing).

* With the hashSeed gone, the 8000955 change [1] should no longer be 
necessary, and we can go back to using the key's hash value stored in 
Entry.hash instead of re-calculating it.

I also removed tests (or test @runs) which are now obsolete.

Automated build and test runs look good.


Webrev:
http://cr.openjdk.java.net/~bchristi/8024009/webrev.00/

Thanks,
-Brent

[1] http://hg.openjdk.java.net/jdk8/jdk8/jdk/rev/5eed4a92ca8c