RFR: 8301992: Embed SymbolTable CHT node [v2]

[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:

  @coleenp and @iklam comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12562/files
  - new: https://git.openjdk.org/jdk/pull/12562/files/5c7a5845..f7a7812e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12562&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12562&range=00-01

  Stats: 12 lines in 3 files changed: 2 ins; 0 del; 10 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