[jfx17u] RFR: 8304098: [testbug] Test compilation failure in ControlUtils.java after JDK-8292353

[Johan Vos]

Remove new instanceof pattern (which is not supported in 11)
Fix JDK-8304098

-------------

Commit messages:
 - Remove new instanceof pattern (which is not supported in 11)

Changes: https://git.openjdk.org/jfx17u/pull/129/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx17u&pr=129&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304098
  Stats: 12 lines in 2 files changed: 6 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jfx17u/pull/129.diff
  Fetch: git fetch https://git.openjdk.org/jfx17u pull/129/head:pull/129

PR: https://git.openjdk.org/jfx17u/pull/129