[regexp] Port RegExpExecStub to CSA (mostly)

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 2f196c3b1d9351fa7516effab35eb67b27e3d634..c31838661f1e9ec06a19965550c301c5bd03c6d3 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -647,9 +647,15 @@ class CallConstructDescriptor : public CallInterfaceDescriptor {
 
 class RegExpExecDescriptor : public CallInterfaceDescriptor {
  public:
-  DEFINE_PARAMETERS(kRegExpObject, kString, kPreviousIndex, kLastMatchInfo)
-  DECLARE_DESCRIPTOR_WITH_STACK_ARGS(RegExpExecDescriptor,
-                                     CallInterfaceDescriptor)
+  DEFINE_PARAMETERS(kString, kLastIndex, kStringStart, kStringEnd, kCode)
+  DECLARE_DESCRIPTOR_WITH_CUSTOM_FUNCTION_TYPE(RegExpExecDescriptor,
+                                               CallInterfaceDescriptor)
+
+  static const Register StringRegister();
+  static const Register LastIndexRegister();
+  static const Register StringStartRegister();
+  static const Register StringEndRegister();
+  static const Register CodeRegister();
 };
 
 class RegExpReplaceDescriptor : public CallInterfaceDescriptor {