[regexp] Remove IsRegExp intrinsic

src/compiler/js-intrinsic-lowering.cc

Index: src/compiler/js-intrinsic-lowering.cc
diff --git a/src/compiler/js-intrinsic-lowering.cc b/src/compiler/js-intrinsic-lowering.cc
index 3b1bd285aa39f8e0a29f4f7b106114ea7c2621a2..9a1fe0a8b6fa4e4e12b8dde28101c1b96cc40b92 100644
--- a/src/compiler/js-intrinsic-lowering.cc
+++ b/src/compiler/js-intrinsic-lowering.cc
@@ -46,8 +46,6 @@ Reduction JSIntrinsicLowering::Reduce(Node* node) {
       return ReduceIsInstanceType(node, JS_ARRAY_TYPE);
     case Runtime::kInlineIsTypedArray:
       return ReduceIsInstanceType(node, JS_TYPED_ARRAY_TYPE);
-    case Runtime::kInlineIsRegExp:
-      return ReduceIsInstanceType(node, JS_REGEXP_TYPE);
     case Runtime::kInlineIsJSReceiver:
       return ReduceIsJSReceiver(node);
     case Runtime::kInlineIsSmi: