[regexp] Add slow exec stub to reduce code size

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 016ae62d24c04feb0b25660f8248367d27866936..95ebb4976ca33c0b2798c5590d992a61b09e8b43 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -50,6 +50,7 @@ class PlatformInterfaceDescriptor;
   V(ConstructStub)                         \
   V(ConstructTrampoline)                   \
   V(RegExpExec)                            \
+  V(RegExpPrototypeExecSlow)               \
   V(RegExpReplace)                         \
   V(RegExpSplit)                           \
   V(CopyFastSmiOrObjectElements)           \
@@ -658,6 +659,13 @@ class RegExpExecDescriptor : public CallInterfaceDescriptor {
   static const Register CodeRegister();
 };
 
+class RegExpPrototypeExecSlowDescriptor : public CallInterfaceDescriptor {
+ public:
+  DEFINE_PARAMETERS(kReceiver, kString)
+  DECLARE_DEFAULT_DESCRIPTOR(RegExpPrototypeExecSlowDescriptor,
+                             CallInterfaceDescriptor, kParameterCount)
+};
+
 class RegExpReplaceDescriptor : public CallInterfaceDescriptor {
  public:
   DEFINE_PARAMETERS(kReceiver, kString, kReplaceValue)