Cleaning up the branches

[Brian Goetz]

I did a `branch -r` on our new openjdk/amber git repository, and got:

origin/HEAD -> origin/master
   origin/amber-demo
   origin/amber-demo-II
   origin/asm-condy
   origin/concise-method-declarations
   origin/condy
   origin/condy-folding
   origin/condy-folding-new
   origin/condy-lambda
   origin/datum
   origin/datum-old
   origin/enhanced-enums
   origin/intrinsics
   origin/intrinsics-project
   origin/jep-334
   origin/lambda-leftovers
   origin/local-methods
   origin/lvti
   origin/master
   origin/newescapes
   origin/pattern-runtime
   origin/patterns
   origin/patterns-deconstruction
   origin/patterns-stage-1
   origin/patterns-stage-2
   origin/raw-string-literal
   origin/records
   origin/records-2
   origin/records-and-sealed
   origin/sealed
   origin/sealed-types
   origin/stats-before-this-super
   origin/string-tapas
   origin/switch
   origin/switch2

Amber has had a lot of experiments already, some of which graduated to 
features, and others of which have withered.  Given that there will be 
more work in the future, some "clean up our workshop" may be in order.  
Let's set out some goals.

1.  Being able to find what you want.  I am not going to advocate for a 
mandatory structure for branch names, but clearly having two branches 
with very similar names (like `sealed` and `sealed-types`, or 
`intrinsics` and `intrinsics-project`) is confusing; if someone wants to 
check out the latest, they won't know which to pick.

2.  Telling what is active.  Many of these branches will not see further 
work; they were experiments that either succeeded or failed, but are 
completed.  They may have historical value, but it would be good to be 
able to know what is still active.


Without getting into too much of a bikeshed (hah), some simple proposals:

  - When a branch becomes (or is recognized to be) dead, let's rename it 
to something that makes that clear, such as `dead-x` where `x` is the 
old name.  (IF `dead` started with `z`, that would be better, as they 
would all sort to the bottom.)  This is an action that can be done by 
any committer, so we can all help keep the workshop clean.

  - If you have a private branch, keep it in your private fork. We 
couldn't do this with `hg`, but we can with `git`, so if any of the 
above are private forks in disguise, let's move them to your private git 
fork, and apply the `dead-x` treatment to it.

  - For the active branches, maybe we can keep a wiki page with the list 
of branches, what they actually are, what is their disposition, if 
anything (e.g., graduated as part of JEP-xxx), and who is the most 
relevant authority on their state?  Then we would know who to ask if 
it's dead.