[regexp] Remove remainder of native RegExpExecStub

src/mips/interface-descriptors-mips.cc

Index: src/mips/interface-descriptors-mips.cc
diff --git a/src/mips/interface-descriptors-mips.cc b/src/mips/interface-descriptors-mips.cc
index 6e77ee835a89ef49f0bc448baa9dc84fb1c007d7..2fea9a84a6ab429745daf2238b7166e7541016ee 100644
--- a/src/mips/interface-descriptors-mips.cc
+++ b/src/mips/interface-descriptors-mips.cc
@@ -56,11 +56,6 @@ const Register MathPowIntegerDescriptor::exponent() {
   return MathPowTaggedDescriptor::exponent();
 }
 
-const Register RegExpExecDescriptor::StringRegister() { return a0; }
-const Register RegExpExecDescriptor::LastIndexRegister() { return a1; }
-const Register RegExpExecDescriptor::StringStartRegister() { return a2; }
-const Register RegExpExecDescriptor::StringEndRegister() { return a3; }
-const Register RegExpExecDescriptor::CodeRegister() { return t0; }
 
 const Register GrowArrayElementsDescriptor::ObjectRegister() { return a0; }
 const Register GrowArrayElementsDescriptor::KeyRegister() { return a3; }