add gc test

Author: bonede

tree-sitter/src/test/java/org/treesitter/GCTest.java

@@ -0,0 +1,11 @@
+package org.treesitter;
+
+import org.junit.jupiter.api.Test;
+
+public class GCTest {
+    @Test
+    void gc(){
+        // Force system to gc to test invalid pointers;
+        System.gc();
+    }
+}