RFR: 8301992: Embed SymbolTable CHT node [v4]

[Calvin Cheung]

> Please review this patch for embedding the Symbol inside a ConcurrentHashTable Node instead of having a pointer to a Symbol. This eliminates malloc/free for each Symbol.
> 
> This patch is co-authored by @robehn.
> 
> Passed tiers 1 - 4 testing.

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  add Afree() for permanent symbols

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12562/files
  - new: https://git.openjdk.org/jdk/pull/12562/files/9b4c63d9..b22eb3b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12562&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12562&range=02-03

  Stats: 10 lines in 1 file changed: 9 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12562.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12562/head:pull/12562

PR: https://git.openjdk.org/jdk/pull/12562