Use sleep instead of yield.

Be less at the mercy of the kernel scheduler and
thread priorities (JIT thread is lower priority).

Test: test.py --jit
Change-Id: I20ccd7ece6ea605ce42f8a16ec23bb377b92e653
diff --git a/test/655-jit-clinit/src/Main.java b/test/655-jit-clinit/src/Main.java
index 5d32180..44b3154 100644
--- a/test/655-jit-clinit/src/Main.java
+++ b/test/655-jit-clinit/src/Main.java
@@ -38,7 +38,12 @@
     array = new Object[10000];
     while (!Main.isJitCompiled(Foo.class, "hotMethod")) {
       Foo.hotMethod();
-      Thread.yield();
+      try {
+        // Sleep to give a chance for the JIT to compile `hotMethod`.
+        Thread.sleep(100);
+      } catch (Exception e) {
+        // Ignore
+      }
     }
   }