[builtins] move PromiseBuiltinsAssembler to it's own header file

test/cctest/test-code-stub-assembler.cc

Index: test/cctest/test-code-stub-assembler.cc
diff --git a/test/cctest/test-code-stub-assembler.cc b/test/cctest/test-code-stub-assembler.cc
index 4c78ab38c03db1ac9d8c1ba4cc920b3b1718eed1..84f4f5641a9da62308bcedabe3de7b51845b70a3 100644
--- a/test/cctest/test-code-stub-assembler.cc
+++ b/test/cctest/test-code-stub-assembler.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "src/base/utils/random-number-generator.h"
+#include "src/builtins/builtins-promise.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 #include "src/compiler/node.h"
@@ -1974,5 +1975,26 @@ TEST(IsPrivateSymbol) {
   CHECK_EQ(isolate->heap()->true_value(), *result);
 }
 
+TEST(PromiseHasHandler) {
+  Isolate* isolate(CcTest::InitIsolateOnce());
+
+  const int kNumParams = 1;
+  CodeAssemblerTester data(isolate, kNumParams);
+  PromiseBuiltinsAssembler m(data.state());
+
+  Node* const context = m.Parameter(kNumParams + 2);
+  Node* const promise = m.AllocateJSPromise(context);
+  m.PromiseInit(promise);
+  m.Return(m.SelectBooleanConstant(m.PromiseHasHandler(promise)));
+
+  Handle<Code> code = data.GenerateCode();
+  CHECK(!code.is_null());
+
+  FunctionTester ft(code, kNumParams);
+  Handle<Object> result =
+      ft.Call(isolate->factory()->undefined_value()).ToHandleChecked();
+  CHECK_EQ(isolate->heap()->false_value(), *result);
+}
+
 }  // namespace internal
 }  // namespace v8