[turbofan] Replace uninitialized JSCall nodes with SOFT deopt.

test/cctest/compiler/test-run-unwinding-info.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Test enabled only on supported architectures.
 #if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_ARM) || \
     defined(V8_TARGET_ARCH_ARM64)
 
 #include "src/flags.h"
 #include "src/objects-inl.h"
 #include "src/objects.h"
 #include "src/unicode-cache.h"
 #include "test/cctest/compiler/function-tester.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 TEST(RunUnwindingInfo) {
+  FLAG_always_opt = true;
   FLAG_perf_prof_unwinding_info = true;
 
   FunctionTester tester(
       "(function (x) {\n"
       "  function f(x) { return x*x; }\n"
       "  return x > 0 ? x+1 : f(x);\n"
       "})");
 
   tester.Call(tester.Val(-1));
 
@@ skipping 22 matching lines @@
 //  |   |  State B != A  |---+
 //  |   +----------------+   |
 //  +-->|  Failure here  |<--+
 //      +----------------+
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif