RFR: Do not double deploy the redefineagent

[Eric Caspole]

Adding the <attach>false</attach> to the assembly plugin configuration.

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Commit messages:
 - Do not double deploy the redefineagent

Changes: https://git.openjdk.org/jmh-jdk-microbenchmarks/pull/11/files
 Webrev: https://webrevs.openjdk.org/?repo=jmh-jdk-microbenchmarks&pr=11&range=00
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jmh-jdk-microbenchmarks/pull/11.diff
  Fetch: git fetch https://git.openjdk.org/jmh-jdk-microbenchmarks pull/11/head:pull/11

PR: https://git.openjdk.org/jmh-jdk-microbenchmarks/pull/11