RFR: 8315890: Attempts to load from nullptr in instanceKlass.cpp and unsafe.cpp

[Calvin Cheung]

On Fri, 27 Oct 2023 15:40:58 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

> Calls in instanceKlass.cpp and unsafe.cpp try to call an atomic load on method calls that could return nullptr. This patch ensures that nullptr is not passed into the load. Verified with tier1-5 tests.

LGTM

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

Marked as reviewed by ccheung (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16405#pullrequestreview-1702715503