RV32G first PR HOWTO

1. fork the https://github.com/riscv-collab/v8 and get a private v8 repo for yourself
2. follow the https://github.com/riscv-collab/v8/wiki/Getting-Started-for-RV32G-porting, set up the code base
3. create a local foo branch then make your local modify in the foo branch
4. Before local commit, two things must be done firstly：
   • using "git cl format --no-python" to properly format your modify
   • make the local build of riscv32 debug pass
5. local git commit and git push the foo branch to your private v8 repo
6. file Pull Request in the github web page, make sure to invite at least one reviewer ( @yahan or @qjivy )
7. check the status of your PR in the github page, if there is any failure checks, pls resolve it , and repeat the process of the PR (from 3-7) again.