RFR: 8252933: com.sun.tools.jdi.ObjectReferenceImpl#validateAssignment always requests referenceType

[Daniil Titov]

The change fixes the regression introduced by https://bugs.openjdk.java.net/browse/JDK-8241080.

Method validateAssignment() in com.sun.tools.jdi.ObjectReferenceImpl now always retrieves the reference type and that
requires one more JDWP packet if the value is not cached yet. Before https://bugs.openjdk.java.net/browse/JDK-8241080
this happened for arrays only.

Testing: tier1-tier3 tests passes.

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Commit messages:
 - 8252933: com.sun.tools.jdi.ObjectReferenceImpl#validateAssignment always requests referenceType

Changes: https://git.openjdk.java.net/jdk/pull/124/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=124&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252933
  Stats: 6 lines in 1 file changed: 3 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/124.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/124/head:pull/124

PR: https://git.openjdk.java.net/jdk/pull/124