RFR: 8361216: Do not fork javac in J2DBench ant build [v2]

[Eric Caspole]

> Build J2DBench in ant using JAVA_HOME, not using fork to possibly pick a different javac from the PATH.

Eric Caspole has updated the pull request incrementally with one additional commit since the last revision:

  Update the version default to 8 in the Make file as Phil noticed.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26077/files
  - new: https://git.openjdk.org/jdk/pull/26077/files/a2ad30c8..ab69037f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26077&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26077&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26077.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26077/head:pull/26077

PR: https://git.openjdk.org/jdk/pull/26077