RFR: CODETOOLS-7903090: Merge othervm and agentvm classes; eliminate raw types [v2]

[Jonathan Gibbons]

> Please review some moderately simple changes to update the code used in test VMs, hitherto constrained to use JDK 1.2 or 1.5.
> 
> As well as eliminating raw types, the code is converted to use standard Collection classes instead of the old Dictionary and Vector.

Jonathan Gibbons has updated the pull request incrementally with one additional commit since the last revision:

  ensure CLASSDIR created

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Changes:
  - all: https://git.openjdk.java.net/jtreg/pull/49/files
  - new: https://git.openjdk.java.net/jtreg/pull/49/files/f1b761cd..fcc549b9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jtreg&pr=49&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jtreg&pr=49&range=00-01

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jtreg/pull/49.diff
  Fetch: git fetch https://git.openjdk.java.net/jtreg pull/49/head:pull/49

PR: https://git.openjdk.java.net/jtreg/pull/49