[jdk11u-dev] RFR: 8210593: Clean up JNI_ENV_ARG and factorize the macros for vmTestbase/jvmti[N-R] tests

[Goetz Lindenmaier]

I backport this for parity with 11.0.14-oracle.

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Commit messages:
 - Backport 6a2e4311f5f435f3e9513af0f515d41eaf2cb67a

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/645/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=645&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8210593
  Stats: 1051 lines in 50 files changed: 2 ins; 883 del; 166 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/645.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/645/head:pull/645

PR: https://git.openjdk.java.net/jdk11u-dev/pull/645