[turbofan] Avoid dereferencing empty handle when inlining a tail call.

test/mjsunit/regress/regress-crbug-593697-2.js

Index: test/mjsunit/regress/regress-crbug-593697-2.js
diff --git a/test/mjsunit/es6/tail-call-megatest-shard1.js b/test/mjsunit/regress/regress-crbug-593697-2.js
similarity index 50%
copy from test/mjsunit/es6/tail-call-megatest-shard1.js
copy to test/mjsunit/regress/regress-crbug-593697-2.js
index 411925215e654ac7f88588c8fa46bc999be07a05..1fcbaebd83a2caff31f76b02d895d6c16da28ce9 100644
--- a/test/mjsunit/es6/tail-call-megatest-shard1.js
+++ b/test/mjsunit/regress/regress-crbug-593697-2.js
@@ -3,13 +3,16 @@
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax --harmony-tailcalls
-// TODO(v8:4698), TODO(ishell): support these cases.
-// Flags: --turbo --nostress-opt
 
-try {
-  load("mjsunit/es6/tail-call-megatest.js");
-} catch(e) {
-  load("test/mjsunit/es6/tail-call-megatest.js");
-}
+"use strict";
 
-run_tests(1);
+%SetForceInlineFlag(Math.cos);
+
+var f5 = (function f6(stdlib) {
+  "use asm";
+  var cos = stdlib.Math.cos;
+  function f5() {
+    return cos();
+  }
+  return { f5: f5 };
+})(this, {}).f5();