RFR: 8249783: Simplify DerValue and DerInputStream [v3]

[Weijun Wang]

> This code change rewrites DerValue into a mostly immutable class and simplifies DerInputStream as a wrapper for a
> series of DerValues objects. DerInputBuffer is removed.
> All existing methods of DerValue and DerInputStream should still work with the exact same behavior, except for a few
> places where bugs are fixed. For example, Indefinite length must be used with a constructed tag.
> Except for the ObjectIdentifier class where DerInputBuffer is directly referenced, no other code is touched.

Weijun Wang 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 four additional commits since
the last revision:

 - 8249783: Simplify DerValue and DerInputStream
 - Merge remote-tracking branch 'origin/master' into 8249783
 - Enhance DerValue::getOctetString to be able to read multi-level constructed value.
 - 8249783: Simplify DerValue and DerInputStream

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/232/files
  - new: https://git.openjdk.java.net/jdk/pull/232/files/e8f804c6..ac77172e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=232&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=232&range=01-02

  Stats: 13102 lines in 448 files changed: 7078 ins; 4729 del; 1295 mod
  Patch: https://git.openjdk.java.net/jdk/pull/232.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/232/head:pull/232

PR: https://git.openjdk.java.net/jdk/pull/232