RFR: 8364970: Redo JDK-8327381 by updating the CmpU type instead of the Bool type

[Francisco Ferrari Bihurriet]

Hi, this pull request is a second take of 1383fec41756322bf2832c55633e46395b937b40, by updating the `CmpUNode` type as either `TypeInt::CC_LE` (case 1a) or `TypeInt::CC_LT` (case 1b) instead of updating the `BoolNode` type as `TypeInt::ONE`.

With this approach a56cd371a2c497e4323756f8b8a08a0bba059bf2 becomes unnecessary. Additionally, having the right type in `CmpUNode` could potentially enable further optimizations.

#### Testing

In order to evaluate the changes, the following testing has been performed:

* `jdk:tier1` (see [GitHub Actions run](https://github.com/franferrax/jdk/actions/runs/16789994433))
* [`TestBoolNodeGVN.java`](https://github.com/openjdk/jdk/blob/jdk-26+9/test/hotspot/jtreg/compiler/c2/gvn/TestBoolNodeGVN.java), created for [JDK-8327381: Refactor type-improving transformations in BoolNode::Ideal to BoolNode::Value](https://bugs.openjdk.org/browse/JDK-8327381) (1383fec41756322bf2832c55633e46395b937b40)
    * I also checked it breaks if I remove the `CmpUNode::Value_cmpu_and_mask` call
* Private reproducer for [JDK-8349584: Improve compiler processing](https://bugs.openjdk.org/browse/JDK-8349584) (a56cd371a2c497e4323756f8b8a08a0bba059bf2)
* A local slowdebug run of the `test/hotspot/jtreg/compiler/c2` category on _Fedora Linux x86_64_
    * Same results as with `master` (f95af744b07a9ec87e2507b3d584cbcddc827bbd)

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

Commit messages:
 - 8364970: Redo JDK-8327381 by updating the CmpU type instead of the Bool type
 - Revert "8349584: Improve compiler processing"

Changes: https://git.openjdk.org/jdk/pull/26666/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26666&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364970
  Stats: 227 lines in 4 files changed: 80 ins; 145 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26666.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26666/head:pull/26666

PR: https://git.openjdk.org/jdk/pull/26666