RFR: 8191786: Thread-SMR hash table size should be dynamic

[Daniel D.Daugherty]

Small change to switch Thread-SMR's hash table from ResourceHashtable to KVHashtable
so that a variable sized hash table is used instead of a fixed size hash table (1031 elements).
Also refactor common hash table size calculation code into static hash_table_size()
function and call it from both places.

Test with Mach5 Tier[1-7] testing.

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Commit messages:
 - 8191786: Thread-SMR hash table size should be dynamic

Changes: https://git.openjdk.java.net/jdk/pull/4168/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4168&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8191786
  Stats: 55 lines in 1 file changed: 17 ins; 15 del; 23 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4168.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4168/head:pull/4168

PR: https://git.openjdk.java.net/jdk/pull/4168