RFR: JDK-8308245: Add -proc:full to describe current default annotation processing policy

[Joe Darcy]

Quick note on this PR: it proposes to add "-proc:full" as a recognized option to explicitly name the current default policy of performing both annotation processing and subsequent compilation.

(It is possible that in a future release, the default will change, in which case having the -proc:full as an option now will was any transition to a new default.)

I tried to write regressions tests to verify that "-proc:none,full" was rejected by javac; it was duly rejected, but rejected with an Error such that the usual compile/fail jtreg tags to did allow the case to pass.

As "-proc:full" corresponds to the current default, there is no new implementation of this policy in the body of the compiler.

Please also review the CSR [JDK-8308346](https://bugs.openjdk.org/browse/JDK-8308346); the CSR lists proposed updates to the javac "man page."

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

Commit messages:
 - JDK-8308245: Add -proc:full to describe current default annotation processing policy

Changes: https://git.openjdk.org/jdk/pull/14044/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14044&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308245
  Stats: 43 lines in 3 files changed: 41 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14044.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14044/head:pull/14044

PR: https://git.openjdk.org/jdk/pull/14044