RFR: [type-classes] 8375482: Basic tests for UnsignedInt [v4]

[Joe Darcy]

> Add some witnesses to UnsignedInt and basic tests.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Fix typo.

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1991/files
  - new: https://git.openjdk.org/valhalla/pull/1991/files/fac238ca..a5f4a1da

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1991&range=03
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1991&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1991.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1991/head:pull/1991

PR: https://git.openjdk.org/valhalla/pull/1991