In preparation of possibly archiving the https://github.com/openjdk/jmh-jdk-microbenchmarks project we need to find a new home for the micros-javac benchmarks.

These javac benchmarks were added after most everything else in jmh-jdk-microbenchmarks was moved into test/micro in the main jdk repo.

As they rely on downloading a lot of source code through a maven antrun and produce a rather bulky benchmarks.jar, the plan is *not* to integrate it with the openjdk make build but to put it in a separate non-jtreg root test folder as-is.