RFR: JDK-8042981: Strip type annotations in Types' utility methods [v6]

[Joe Darcy]

> Early review for JDK-8042981: "Strip type annotations in Types' utility methods". I work more often in the Element world rather than the Type word of the annotation processing APIs.
> 
> The type annotations on primitive types are *not* cleared by the existing annotation clearing mechanisms. I suspect Type.Visitor is missing a case for primitive types. Someone with familiarity with javac's type modeling should take a look; thanks.

Joe Darcy has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:

 - Merge branch 'master' into JDK-8042981
 - Update implementation and tests.
 - Add changes from Liam.
 - Merge branch 'master' into JDK-8042981
 - Intermediate commit; add stripAnnotations method.
 - Merge branch 'master' into JDK-8042981
 - Merge branch 'master' into JDK-8042981
 - Update visitor; all langtools regression tests pass.
 - Merge branch 'master' into JDK-8042981
 - JDK-8042981: Strip type annotations in Types' utility methods

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/8984/files
  - new: https://git.openjdk.org/jdk/pull/8984/files/e9200876..342b091f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=8984&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=8984&range=04-05

  Stats: 11303 lines in 313 files changed: 6324 ins; 3810 del; 1169 mod
  Patch: https://git.openjdk.org/jdk/pull/8984.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/8984/head:pull/8984

PR: https://git.openjdk.org/jdk/pull/8984