RFR: 8344763: cpCache print_on doesn't handle nulls

[Coleen Phillimore]

A change to remove some more security manager code, resulted in java.lang.System not having any more indy instructions so the gtest test_cpCache_output.cpp was crashing because of missing null checks.  Please review this trivial change to add in null checks.  The test doesn't verify that there are indys so doesn't need to be fixed.

Tested with gtest and upcoming security manager change.

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Commit messages:
 - 8344763: cpCache print_on doesn't handle nulls

Changes: https://git.openjdk.org/jdk/pull/22298/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22298&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344763
  Stats: 9 lines in 1 file changed: 6 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/22298.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22298/head:pull/22298

PR: https://git.openjdk.org/jdk/pull/22298