Fix performance characteristics of ArrayList.clear.

PiperOrigin-RevId: 373835131
Change-Id: I377e8a319b8ec144f6aabd13fa40d94b8fac52fb

user/super/com/google/gwt/emul/java/util/ArrayList.java

diff --git a/user/super/com/google/gwt/emul/java/util/ArrayList.java b/user/super/com/google/gwt/emul/java/util/ArrayList.java
index 0180427..c8ced03 100644
--- a/user/super/com/google/gwt/emul/java/util/ArrayList.java
+++ b/user/super/com/google/gwt/emul/java/util/ArrayList.java
@@ -112,7 +112,9 @@
 
   @Override
   public void clear() {
-    array = (E[]) new Object[0];
+    // We are not re-creating the array since ArrayList is expected to preserve it is capacity on
+    // clear and re-creating will change the performance characteristics in J2Wasm.
+    setSize(0);
   }
 
   public Object clone() {