[regexp] Remove unused code

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 5645ca205fee0d817acf56be85f0afbf6d02a01a..8efe7c8a699cb8bad4eddc9c07c587c2a8ba4ab2 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -49,7 +49,6 @@ class PlatformInterfaceDescriptor;
   V(ConstructStub)                        \
   V(ConstructTrampoline)                  \
   V(RegExpExec)                           \
-  V(RegExpConstructResult)                \
   V(CopyFastSmiOrObjectElements)          \
   V(TransitionElementsKind)               \
   V(AllocateHeapNumber)                   \
@@ -571,12 +570,6 @@ class RegExpExecDescriptor : public CallInterfaceDescriptor {
                                      CallInterfaceDescriptor)
 };
 
-class RegExpConstructResultDescriptor : public CallInterfaceDescriptor {
- public:
-  DEFINE_PARAMETERS(kLength, kIndex, kInput)
-  DECLARE_DESCRIPTOR(RegExpConstructResultDescriptor, CallInterfaceDescriptor)
-};
-
 class CopyFastSmiOrObjectElementsDescriptor : public CallInterfaceDescriptor {
  public:
   DEFINE_PARAMETERS(kObject)