RFR 8214449: Make alt_hash a regular immutable member of inner hash table

[Gerard Ziemski]

Hi all,

Please review this followup to JDK-8195100 (Use a low latency hashtable for SymbolTable)

Here we make the “_alt_hash” an immutable and regular field (i.e. non static) of the inner hashtable, to avoid manipulating it from outside and possibly getting it wrong.

This issue affects both Symbol and String hashtable.

Issue:   https://bugs.openjdk.java.net/browse/JDK-8214449
Webrev:  http://cr.openjdk.java.net/~gziemski/8214449_rev1
Testing: Mach5 hs_tier1,2,3,4,5


Cheers