[lworld] Integrated: 8267542: [lworld] [lqagain] javac emits useless checkcast when accessing fields through the reference projection

[Srikanth Adayapalam]

Emit the checkcast only when the class files are bifurcated.

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Commit messages:
 - 8267542: [lworld] [lqagain] javac emits useless checkcast when accessing fields through the reference projection

Changes: https://git.openjdk.java.net/valhalla/pull/423/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=423&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267542
  Stats: 246 lines in 3 files changed: 244 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/423.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/423/head:pull/423

PR: https://git.openjdk.java.net/valhalla/pull/423