[stubs] Cleanup CSA::BitFieldDecode() and friends.

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

 // Copyright 2015 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.
 
 #include "src/base/utils/random-number-generator.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 #include "src/compiler/node.h"
 #include "src/ic/stub-cache.h"
 #include "src/isolate.h"
@@ skipping 43 matching lines @@
   CodeStubAssemblerTester m(isolate, descriptor);
   Handle<HeapObject> undefined = isolate->factory()->undefined_value();
   m.Return(m.SmiTag(m.LoadInstanceType(m.HeapConstant(undefined))));
   Handle<Code> code = m.GenerateCode();
   FunctionTester ft(descriptor, code);
   MaybeHandle<Object> result = ft.Call();
   CHECK_EQ(InstanceType::ODDBALL_TYPE,
            Handle<Smi>::cast(result.ToHandleChecked())->value());
 }
 
-TEST(BitFieldDecode) {
+TEST(DecodeWordFromWord32) {
   Isolate* isolate(CcTest::InitIsolateOnce());
   VoidDescriptor descriptor(isolate);
   CodeStubAssemblerTester m(isolate, descriptor);
 
   class TestBitField : public BitField<unsigned, 3, 3> {};
-  m.Return(m.SmiTag(m.BitFieldDecode<TestBitField>(m.Int32Constant(0x2f))));
+  m.Return(
+      m.SmiTag(m.DecodeWordFromWord32<TestBitField>(m.Int32Constant(0x2f))));
   Handle<Code> code = m.GenerateCode();
   FunctionTester ft(descriptor, code);
   MaybeHandle<Object> result = ft.Call();
   // value  = 00101111
   // mask   = 00111000
   // result = 101
   CHECK_EQ(5, Handle<Smi>::cast(result.ToHandleChecked())->value());
 }
 
 TEST(JSFunction) {
@@ skipping 1541 matching lines @@
             .ToHandleChecked());
     VERIFY(result, object->map(), object->properties(), object->elements());
 #ifdef VERIFY_HEAP
     isolate->heap()->Verify();
 #endif
   }
 }
 
 }  // namespace internal
 }  // namespace v8