RFR: 8267089: Use typedef KVHashtable for ID2KlassTable [v2]

[Yi Yang]

> While backporting some stuff to jdk11, I noticed main functionalities of ID2KlassTable have been removed afterJDK-8213587, it seems that we can use a simple typedef KVHashtable instead.

Yi Yang has updated the pull request incrementally with one additional commit since the last revision:

  ID2KlassTable* instead of ID2KlassTable *

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4007/files
  - new: https://git.openjdk.java.net/jdk/pull/4007/files/8a1b16bd..dcd4564c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4007&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4007&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4007.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4007/head:pull/4007

PR: https://git.openjdk.java.net/jdk/pull/4007