RFR: 8341775: Duplicate manifest files are removed by jarsigner after signing [v7]

[Kevin Driver]

> JDK-8341775: In the case where there is a *single* META-INF directory but potentially *multiple* manifest files of different cases, print a warning before selecting the first one and ignoring the rest (the current behavior should be maintained).
> 
> **Note**: We cannot (so far) pass whether the verbose flag is set to the class that does this processing. We may want to add a property to the builder for this. As-is, the message will be printed via `System.err` whether verbose is set or not.

Kevin Driver has updated the pull request incrementally with three additional commits since the last revision:

 - force-add jar
 - re-write to make the changes in the jarsigner tool itself, rather than the API
 - Revert "JDK-8341775: In the case where there is a *single* META-INF directory but potentially *multiple* manifest files of different cases, print a warning before selecting the first one and ignoring the rest."
   
   This reverts commit 06e90503f3e75b1b432ec0a196716f01ebb7344a.
   
   # Please enter the commit message for your changes. Lines starting
   # with '#' will be kept; you may remove them yourself if you want to.
   # An empty message aborts the commit.
   #
   # On branch 8341775
   # Your branch is up to date with 'origin/8341775'.
   #
   # Changes to be committed:
   #	modified:   src/jdk.jartool/share/classes/jdk/security/jarsigner/JarSigner.java
   #

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22222/files
  - new: https://git.openjdk.org/jdk/pull/22222/files/2b133a31..4c78b9fd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22222&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22222&range=05-06

  Stats: 114 lines in 5 files changed: 96 ins; 17 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22222.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22222/head:pull/22222

PR: https://git.openjdk.org/jdk/pull/22222