Force JIT compilation in 680-checker-deopt-dex-pc-0.

Do not rely on reaching the JIT threshold as this can
take a long time and time out on heavily loaded hosts.

Test: testrunner.py --host -t 680-checker-deopt-dex-pc-0 \
      --runtime-option:-Xjitthreshold:0
Bug: 62611253

Change-Id: Ib180b61744e832779e577c86a39b476cb3856198
diff --git a/test/680-checker-deopt-dex-pc-0/src/Main.java b/test/680-checker-deopt-dex-pc-0/src/Main.java
index d5a6a90..64a3cb3 100644
--- a/test/680-checker-deopt-dex-pc-0/src/Main.java
+++ b/test/680-checker-deopt-dex-pc-0/src/Main.java
@@ -31,15 +31,12 @@
         System.loadLibrary(args[0]);
         if (hasJit()) {
             byte[] array = { 0, 1, 2, 3 };
-            while (!hasJitCompiledEntrypoint(Main.class, "$noinline$getInt")) {
-                for (int i = 0; i < 10000; ++i) {
-                    if ($noinline$getInt(array, 0) != 0x03020100) {
-                        throw new Error();
-                    }
-                }
-                try {
-                    Thread.sleep(200);
-                } catch (InterruptedException ignored) {}
+            ensureJitCompiled(Main.class, "$noinline$getInt");
+            if (!hasJitCompiledEntrypoint(Main.class, "$noinline$getInt")) {
+                throw new Error("Unexpected entrypoint!");
+            }
+            if ($noinline$getInt(array, 0) != 0x03020100) {
+                throw new Error();
             }
             try {
                 // The HDeoptimize at dex pc 0 was previously handled poorly as the dex pc 0
@@ -56,4 +53,5 @@
 
     public static native boolean hasJit();
     public native static boolean hasJitCompiledEntrypoint(Class<?> cls, String methodName);
+    public native static void ensureJitCompiled(Class<?> cls, String methodName);
 }