RFR: 8312121: Fix -Wconversion warnings in tribool.hpp

[Dean Long]

On Fri, 14 Jul 2023 19:47:39 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> Assigning _value first, and then doing _value | 2 doesn't get -Wconversion warnings.  Also, reduced include file inclusion a little.
> Tested with tier1 on linux-x64-debug, windows-x64-debug, macos-aarch64-debug

Marked as reviewed by dlong (Reviewer).

src/hotspot/share/utilities/tribool.hpp line 44:

> 42:   TriBool() : _value(0) {}
> 43:   TriBool(bool value) : _value(value) {
> 44:     _value = _value | 2;

You can also do like line 39 and use `(u1)(expr) & 3` or `((expr & 3u)` also seems to work.

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PR Review: https://git.openjdk.org/jdk/pull/14892#pullrequestreview-1531210148
PR Review Comment: https://git.openjdk.org/jdk/pull/14892#discussion_r1264277785