[jdk21u-dev] RFR: 8320575: generic type information lost on mandated parameters of record's compact constructors

[Goetz Lindenmaier]

I backport this for parity with 21.0.6-oracle.

As the CSR for 21 says, I omit the specification changes. 
These make the description more precise. As I understand,
the change brought to 21 is ok with the broader, unchanged 
specification.

The rest applied clean.

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Commit messages:
 - Backport  7bf1989f59695c3d08b4bd116fb4c022cf9661f4

Changes: https://git.openjdk.org/jdk21u-dev/pull/1026/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1026&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320575
  Stats: 107 lines in 2 files changed: 89 ins; 6 del; 12 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1026.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1026/head:pull/1026

PR: https://git.openjdk.org/jdk21u-dev/pull/1026