[refactoring] Remove unused CSA methods.

Bug: v8:7570
Change-Id: I2c6551fdd1a53323065f9c23e5bee793e9f561cf
Reviewed-on: https://chromium-review.googlesource.com/1032774Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#52850}

src/code-stub-assembler.cc

@@ -911,13 +911,6 @@ void CodeStubAssembler::BranchIfJSReceiver(Node* object, Label* if_true,
   Branch(IsJSReceiver(object), if_true, if_false);
 }
 
-void CodeStubAssembler::BranchIfJSObject(Node* object, Label* if_true,
-                                         Label* if_false) {
-  GotoIf(TaggedIsSmi(object), if_false);
-  STATIC_ASSERT(LAST_JS_OBJECT_TYPE == LAST_TYPE);
-  Branch(IsJSObject(object), if_true, if_false);
-}
-
 TNode<BoolT> CodeStubAssembler::IsFastJSArray(SloppyTNode<Object> object,
                                               SloppyTNode<Context> context) {
   Label if_true(this), if_false(this, Label::kDeferred), exit(this);

src/code-stub-assembler.h

@@ -482,7 +482,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   void BranchIfToBooleanIsTrue(Node* value, Label* if_true, Label* if_false);
 
   void BranchIfJSReceiver(Node* object, Label* if_true, Label* if_false);
-  void BranchIfJSObject(Node* object, Label* if_true, Label* if_false);
 
   void BranchIfFastJSArray(Node* object, Node* context, Label* if_true,
                            Label* if_false);