Map Zulu x86 architecture to i686 for Azul Metadata API

The Azul Metadata API's `arch=x86` returns both 32-bit (i686) and 64-bit
(x64) packages. Because the two variants share identical java_version and
distro_version, setup-java cannot distinguish them and may resolve an
explicit `architecture: x86` request to a 64-bit JDK (and for Java 21+,
where 32-bit is dropped, x86 silently returns x64 instead of failing).

The legacy Zulu Discovery API used `arch=x86&hw_bitness=32` to target only
32-bit builds. The Metadata API exposes the equivalent via `arch=i686`,
which returns only genuine 32-bit builds with full version parity to the
old behavior. Map x86 -> i686 to restore correct 32-bit resolution.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

dist/setup/index.js

@@ -131465,7 +131465,11 @@ class ZuluDistribution extends JavaBase {
             case 'x64':
                 return 'x64';
             case 'x86':
-                return 'x86';
+                // The Azul Metadata API's "x86" value returns both 32-bit (i686) and
+                // 64-bit (x64) packages, which are indistinguishable by version and
+                // would let a 32-bit request resolve to a 64-bit JDK. Use "i686" to
+                // target only genuine 32-bit builds, matching the legacy API behavior.
+                return 'i686';
             case 'aarch64':
             case 'arm64':
                 return 'aarch64';