[jdk21u-dev] RFR: 8331518: Tests should not use the "Classpath" exception form of the legal header

[Andrew Lu]

test/hotspot/jtreg/compiler/codegen/TestConvertImplicitNullCheck.java
test/micro/org/openjdk/bench/java/lang/foreign/libToJavaString.c
test/micro/org/openjdk/bench/vm/compiler/MergeStores.java
have not been added, so ignore.

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

Commit messages:
 - Backport d3bf52628efb79e1b98749d628c4b6d035e1d511

Changes: https://git.openjdk.org/jdk21u-dev/pull/821/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=821&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331518
  Stats: 6 lines in 2 files changed: 0 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/821.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/821/head:pull/821

PR: https://git.openjdk.org/jdk21u-dev/pull/821