RFR: 7903124: Add additional helper methods to TestEnvironment

[Dmitry Bessonov]

7903124: Add additional helper methods to TestEnvironment

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Commit messages:
 - 7903124: Add additional helper methods to TestEnvironment
 - 7903124: Add additional helper methods to TestEnvironment

Changes: https://git.openjdk.java.net/jtharness/pull/25/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jtharness&pr=25&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903124
  Stats: 147 lines in 1 file changed: 147 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jtharness/pull/25.diff
  Fetch: git fetch https://git.openjdk.java.net/jtharness pull/25/head:pull/25

PR: https://git.openjdk.java.net/jtharness/pull/25