RFR: 8267582: BasicLookAndFeel should not call getComponentPopupMenu twice to get a popup menu [v2]

[SWinxy]

> Please review this small change to cache a component's popup menu in BLAF.

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

  Single-class imports

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12017/files
  - new: https://git.openjdk.org/jdk/pull/12017/files/a17c4cdb..37746f07

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12017&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12017&range=00-01

  Stats: 41 lines in 1 file changed: 36 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/12017.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12017/head:pull/12017

PR: https://git.openjdk.org/jdk/pull/12017