RFR: 8320575: generic type information lost on mandated parameters [v11]

[Vicente Romero]

> Reflection is not retrieving generic type information for mandated parameters. This is a known issue which has been explicitly stated in the API of some reflection methods. Fix for [JDK-8292275](https://bugs.openjdk.org/browse/JDK-8292275) made the parameters of compact constructors of record classes `mandated` as specified in the spec. But this implied that users that previous to this change could retrieve the generic type of parameters of compact constructors now they can't anymore. The proposed fix is to try to retrieve generic type information for mandated parameters if available plus changing the spec of the related reflection methods.
> 
> TIA

Vicente Romero 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 11 additional commits since the last revision:

 - Merge branch 'master' into JDK-8320575
 - adding comment to jcod file
 - adding a comment to the test
 - addressing review comments
 - fixing comment
 - simplifying code
 - removing comment
 - javadoc
 - javadoc
 - javadoc adjustments
 - ... and 1 more: https://git.openjdk.org/jdk/compare/23c8a258...508f0199

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17070/files
  - new: https://git.openjdk.org/jdk/pull/17070/files/f6e837d3..508f0199

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17070&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17070&range=09-10

  Stats: 682824 lines in 8459 files changed: 153181 ins; 165583 del; 364060 mod
  Patch: https://git.openjdk.org/jdk/pull/17070.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17070/head:pull/17070

PR: https://git.openjdk.org/jdk/pull/17070