RFR: 8277803: vmTestbase/nsk/jdi/TypeComponent/isSynthetic/issynthetic001 fails with "Synthetic fields not found"

[Liam Miller-Cushon]

This change fixes `vmTestbase/nsk/jdi/TypeComponent/isSynthetic/issynthetic001` after [JDK-8271623](https://bugs.openjdk.java.net/browse/JDK-8271623).

[JDK-8271623](https://bugs.openjdk.java.net/browse/JDK-8271623) causes javac to omit a synthetic field from inner classes that do not reference their enclosing instance. The test was specifically checking for the presence of the synthetic field. To fix the test, this change adds an explicit reference to the enclosing instance of an inner class.

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Commit messages:
 - vmTestbase/nsk/jdi/TypeComponent/isSynthetic/issynthetic001 fails with "Synthetic fields not found"

Changes: https://git.openjdk.java.net/jdk/pull/6601/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6601&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277803
  Stats: 7 lines in 2 files changed: 6 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6601.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6601/head:pull/6601

PR: https://git.openjdk.java.net/jdk/pull/6601