RFR: [type-classes] 8377311: Add equals and hashCode methods for UnsignedInt and ExactInt

[Joe Darcy]

Add accidentally omitted methods.

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Commit messages:
 - 8377311: Add equals and hashCode methods for UnsignedInt and ExactInt

Changes: https://git.openjdk.org/valhalla/pull/2050/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2050&range=00
  Stats: 42 lines in 2 files changed: 40 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/valhalla/pull/2050.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2050/head:pull/2050

PR: https://git.openjdk.org/valhalla/pull/2050