RFR: Adding troubleshooting section to README.md [v2]

[Adam Sotona]

> Hi,
> based on an external contributor recent experience with javac benchmarking javac using jmh-jdk-microbenchmarks I've created a troubleshooting section of the README.md
> 
> Thanks,
> Adam

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  Fixed troubleshooting section in README.md

-------------

Changes:
  - all: https://git.openjdk.java.net/jmh-jdk-microbenchmarks/pull/5/files
  - new: https://git.openjdk.java.net/jmh-jdk-microbenchmarks/pull/5/files/c63a764c..f2e85bb1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmh-jdk-microbenchmarks&pr=5&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jmh-jdk-microbenchmarks&pr=5&range=00-01

  Stats: 8 lines in 1 file changed: 0 ins; 5 del; 3 mod
  Patch: https://git.openjdk.java.net/jmh-jdk-microbenchmarks/pull/5.diff
  Fetch: git fetch https://git.openjdk.java.net/jmh-jdk-microbenchmarks pull/5/head:pull/5

PR: https://git.openjdk.java.net/jmh-jdk-microbenchmarks/pull/5