Revert JVM-based Gradle distribution picker, pin to 8.14.4

Replaces the per-JVM-version dispatch added in #7534 with a single
hardcoded Gradle distribution. Removes the now-unused helpers and
their test.

Author: timtebeek

rewrite-gradle-tooling-model/model/src/main/java/org/openrewrite/gradle/toolingapi/OpenRewriteModelBuilder.java

@@ -82,7 +82,7 @@ public static OpenRewriteModel forProjectDirectory(File projectDir, @Nullable Fi
         } else if (Files.exists(projectDir.toPath().resolve("gradle/wrapper/gradle-wrapper.properties"))) {
             connector.useBuildDistribution();
         } else {
-            connector.useGradleVersion(defaultGradleVersion());
+            connector.useGradleVersion("8.14.4");
         }
         connector
                 // Uncomment to hit breakpoints inside OpenRewriteModelBuilder in unit tests
@@ -132,34 +132,6 @@ public static OpenRewriteModel forProjectDirectory(File projectDir, @Nullable Fi
         }
     }
 
-    /**
-     * Pick a Gradle distribution compatible with the JVM running the Tooling API client.
-     * The daemon defaults to the same JVM as the client, so the chosen distribution must support that Java version.
-     * See <a href="https://docs.gradle.org/current/userguide/compatibility.html">Gradle compatibility matrix</a>.
-     */
-    static String defaultGradleVersion() {
-        return defaultGradleVersion(javaSpecificationVersion());
-    }
-
-    static String defaultGradleVersion(int javaFeatureVersion) {
-        if (javaFeatureVersion >= 25) {
-            return "9.1.0";
-        }
-        return "8.14.3";
-    }
-
-    private static int javaSpecificationVersion() {
-        String version = System.getProperty("java.specification.version", "8");
-        if (version.startsWith("1.")) {
-            version = version.substring(2);
-        }
-        try {
-            return Integer.parseInt(version);
-        } catch (NumberFormatException e) {
-            return 8;
-        }
-    }
-
     /**
      * Everywhere except within openrewrite/rewrite itself the plugin will be resolved from some artifact repository
      * But within openrewrite/rewrite it comes from a build directory.