Reduce array size in test 597-deopt-busy-loop/SimdLoop.

Let the test pass in GC-stress configurations.

Test: testrunner.py --host --gcstress -t 597-deopt-busy-loop
Bug: 138601207
Change-Id: I1f3ca293b17fcc94b437da6ff0b37f9ce1c64179
diff --git a/test/597-deopt-busy-loop/src/SimdLoop.java b/test/597-deopt-busy-loop/src/SimdLoop.java
index ecddfb9..3acf151 100644
--- a/test/597-deopt-busy-loop/src/SimdLoop.java
+++ b/test/597-deopt-busy-loop/src/SimdLoop.java
@@ -40,7 +40,7 @@
         System.out.println("Simd loop finishing");
     }
 
-    static final int kArraySize = 10000000;
+    static final int kArraySize = 3000000;
 
     public void expectEqual(int value, int expected) {
         if (value != expected) {