[test] Test expectations in cctest should use CHECK and not DCHECK.

test/cctest/test-sampler-api.cc

Index: test/cctest/test-sampler-api.cc
diff --git a/test/cctest/test-sampler-api.cc b/test/cctest/test-sampler-api.cc
index 3506c4b38bf330463c3d7609efb8cc3a1ed0a887..14436c5d9d43552b60d927e4caf0533b791db95f 100644
--- a/test/cctest/test-sampler-api.cc
+++ b/test/cctest/test-sampler-api.cc
@@ -94,7 +94,7 @@ class SamplingTestHelper {
 
   explicit SamplingTestHelper(const std::string& test_function)
       : sample_is_taken_(false), isolate_(CcTest::isolate()) {
-    DCHECK(!instance_);
+    CHECK(!instance_);
     instance_ = this;
     v8::HandleScope scope(isolate_);
     v8::Local<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate_);