[jdk15u-dev] RFR: 8266170: -Wnonnull happens in classLoaderData.inline.hpp

[Roman Marchenko]

Backport of JDK-8272720 to 15u
Applied cleanely, no tier1 tests regressions.

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Commit messages:
 - Backport a1c942c02b65a7fc2a837d2bb43fa134dadcad11

Changes: https://git.openjdk.org/jdk15u-dev/pull/279/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk15u-dev&pr=279&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8266170
  Stats: 3 lines in 1 file changed: 0 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk15u-dev/pull/279.diff
  Fetch: git fetch https://git.openjdk.org/jdk15u-dev pull/279/head:pull/279

PR: https://git.openjdk.org/jdk15u-dev/pull/279