RFR: 8253060: remove test/hotspot/jtreg/test_env.sh

[Igor Ignatyev]

[JDK-8252402](https://bugs.openjdk.java.net/browse/JDK-8252402) removed the last shell test from `test/hotspot/jtreg`,
and now `test_env.sh` can be removed so it won't trick anyone into believing that shell tests are
acceptable/desirable/supported in hotspot testbase.

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Commit messages:
 - 8253060: remove test/hotspot/jtreg/test_env.sh

Changes: https://git.openjdk.java.net/jdk/pull/132/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=132&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253060
  Stats: 212 lines in 1 file changed: 0 ins; 212 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/132.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/132/head:pull/132

PR: https://git.openjdk.java.net/jdk/pull/132