RFR: CODETOOLS-7903105: remove jtreg Ant task

Wed Feb 16 19:08:49 UTC 2022

Please remove a moderately simple patch to remove the Ant task from `jtreg` and `jtdiff`.

As a result of this, there is no longer any need to pass Ant-related paths into the Makefile.   The Ant binary is still required in `build.sh`, in order to build AsmTools, JCov and JT Harness.

An unexpected side effect was that one of the jtreg, resource files became empty, and could be deleted, with minor consequences in the build and test files as well.

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Commit messages:
 - CODETOOLS-7903105: remove jtreg Ant task

Changes: https://git.openjdk.java.net/jtreg/pull/60/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jtreg&pr=60&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903105
  Stats: 498 lines in 9 files changed: 6 ins; 483 del; 9 mod
  Patch: https://git.openjdk.java.net/jtreg/pull/60.diff
  Fetch: git fetch https://git.openjdk.java.net/jtreg pull/60/head:pull/60

PR: https://git.openjdk.java.net/jtreg/pull/60