Integrated: JDK-8268981: [lworld] UnifiedPrimitiveClassNestHostTest.java should test with the primary mirror

[Mandy Chung]

Fix the bug in test/langtools/tools/javac/valhalla/lworld-values/UnifiedPrimitiveClassNestHostTest.java test that verifies the nest host with a secondary mirror but the core reflection API returns the primary mirror.

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Commit messages:
 - JDK-8268981:  [lworld] UnifiedPrimitiveClassNestHostTest.java should test with the primary mirror

Changes: https://git.openjdk.java.net/valhalla/pull/452/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=452&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268981
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/452.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/452/head:pull/452

PR: https://git.openjdk.java.net/valhalla/pull/452