RFR: 8351276: Prevent redundant computeValue calls when a chain of mappings becomes observed [v2]

[John Hendrikx]

> 8351276: Prevent redundant computeValue calls when a chain of mappings becomes observed

John Hendrikx has updated the pull request incrementally with one additional commit since the last revision:

  Fix review comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1730/files
  - new: https://git.openjdk.org/jfx/pull/1730/files/43e774a4..87e2bd88

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1730&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1730&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1730.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1730/head:pull/1730

PR: https://git.openjdk.org/jfx/pull/1730