Share test fixtures across modules

- Move art.arcane.iris.testsupport into core/src/testFixtures and apply java-test-fixtures to core
- Consume core test fixtures from the bukkit plugin, nms, probe and the three loader adapters
- Delete the duplicate ProjectPaths copies in the bukkit-plugin and modded-common test trees
- Point ModdedMessageContributorTest at the shared ProjectPaths
- Guard CommandPackCompatTest, NativeTransitionColumnTest and StubPlatformStateTest with PlatformLeakGuard
- Release the probe runtime state after DimensionStackSuperflatProbeTest opens a workspace
- Keep core main classes ahead of the core jar on the test classpath so the bytecode gates still scan a directory

probe/build.gradle

@@ -17,6 +17,7 @@ dependencies {
     implementation(project(':core'))
     compileOnly(libs.spigot)
     testImplementation('junit:junit:4.13.2')
+    testImplementation(testFixtures(project(':core')))
     testImplementation(volmLibCoordinate) {
         transitive = false
     }

probe/src/test/java/art/arcane/iris/probe/DimensionStackSuperflatProbeTest.java

@@ -4,6 +4,8 @@ import art.arcane.iris.engine.DimensionStackContext;
 import art.arcane.iris.engine.DimensionStackLayout;
 import art.arcane.iris.engine.framework.Engine;
 import art.arcane.iris.spi.PlatformBlockState;
+import art.arcane.iris.testsupport.IrisRuntimeState;
+import org.junit.AfterClass;
 import org.junit.Test;
 
 import java.io.File;
@@ -20,6 +22,11 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 public final class DimensionStackSuperflatProbeTest {
+    @AfterClass
+    public static void releaseProbeRuntime() {
+        IrisRuntimeState.reset();
+    }
+
     private static final long SEED = 1_337L;
     private static final long ALTERNATE_SEED = 8_675_309L;
     private static final int WORLD_HEIGHT = 128;

probe/src/test/java/art/arcane/iris/probe/StubPlatformStateTest.java

@@ -4,9 +4,11 @@ import art.arcane.iris.engine.decorator.IrisSpeleothems;
 import art.arcane.iris.engine.object.IrisObjectRotation;
 import art.arcane.iris.spi.IrisPlatforms;
 import art.arcane.iris.spi.PlatformBlockState;
+import art.arcane.iris.testsupport.PlatformLeakGuard;
 import art.arcane.iris.util.project.hunk.Hunk;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
+import org.junit.ClassRule;
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
@@ -15,9 +17,11 @@ import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 
 public final class StubPlatformStateTest {
+    @ClassRule
+    public static final PlatformLeakGuard LEAK_GUARD = PlatformLeakGuard.clean();
+
     @BeforeClass
     public static void bindPlatform() {
-        IrisPlatforms.unbind();
         IrisPlatforms.bind(new StubPlatform());
         StubPlatform.bindGenerationStateHandlers();
     }