Revert of [regexp] Remove remainder of native RegExpExecStub

src/s390/interface-descriptors-s390.cc

Index: src/s390/interface-descriptors-s390.cc
diff --git a/src/s390/interface-descriptors-s390.cc b/src/s390/interface-descriptors-s390.cc
index 031ccafe6f6fb60193c55c6c06364c7b9f65a9c3..091a64583a6891793f7e7d9e70aa08d56cdfebf9 100644
--- a/src/s390/interface-descriptors-s390.cc
+++ b/src/s390/interface-descriptors-s390.cc
@@ -55,6 +55,12 @@
 const Register MathPowIntegerDescriptor::exponent() {
   return MathPowTaggedDescriptor::exponent();
 }
+
+const Register RegExpExecDescriptor::StringRegister() { return r2; }
+const Register RegExpExecDescriptor::LastIndexRegister() { return r3; }
+const Register RegExpExecDescriptor::StringStartRegister() { return r4; }
+const Register RegExpExecDescriptor::StringEndRegister() { return r5; }
+const Register RegExpExecDescriptor::CodeRegister() { return r9; }
 
 const Register GrowArrayElementsDescriptor::ObjectRegister() { return r2; }
 const Register GrowArrayElementsDescriptor::KeyRegister() { return r5; }