[regexp] Port RegExpExecStub to CSA (mostly)

src/arm/interface-descriptors-arm.cc

Index: src/arm/interface-descriptors-arm.cc
diff --git a/src/arm/interface-descriptors-arm.cc b/src/arm/interface-descriptors-arm.cc
index 8281f2a43bb82d2ac6420d89df0d50ea59e1ea54..c2c547b1a3b99e4d4cc4d8f247408efa5105c2c7 100644
--- a/src/arm/interface-descriptors-arm.cc
+++ b/src/arm/interface-descriptors-arm.cc
@@ -54,11 +54,15 @@ const Register ApiGetterDescriptor::CallbackRegister() { return r3; }
 
 const Register MathPowTaggedDescriptor::exponent() { return r2; }
 
-
 const Register MathPowIntegerDescriptor::exponent() {
   return MathPowTaggedDescriptor::exponent();
 }
 
+const Register RegExpExecDescriptor::StringRegister() { return r0; }
+const Register RegExpExecDescriptor::LastIndexRegister() { return r1; }
+const Register RegExpExecDescriptor::StringStartRegister() { return r2; }
+const Register RegExpExecDescriptor::StringEndRegister() { return r3; }
+const Register RegExpExecDescriptor::CodeRegister() { return r4; }
 
 const Register GrowArrayElementsDescriptor::ObjectRegister() { return r0; }
 const Register GrowArrayElementsDescriptor::KeyRegister() { return r3; }