[ic] Extract load IC proto array handlers handling to a separate stub.

src/mips64/interface-descriptors-mips64.cc

Index: src/mips64/interface-descriptors-mips64.cc
diff --git a/src/mips64/interface-descriptors-mips64.cc b/src/mips64/interface-descriptors-mips64.cc
index f80e25fc538d1012ca62f51d18f236b2a7916aeb..c6a917f5d46466b80e09151e0cd01aea33f8c28f 100644
--- a/src/mips64/interface-descriptors-mips64.cc
+++ b/src/mips64/interface-descriptors-mips64.cc
@@ -29,9 +29,9 @@ const Register LoadDescriptor::ReceiverRegister() { return a1; }
 const Register LoadDescriptor::NameRegister() { return a2; }
 const Register LoadDescriptor::SlotRegister() { return a0; }
 
-
 const Register LoadWithVectorDescriptor::VectorRegister() { return a3; }
 
+const Register LoadICProtoArrayDescriptor::HandlerRegister() { return a4; }
 
 const Register StoreDescriptor::ReceiverRegister() { return a1; }
 const Register StoreDescriptor::NameRegister() { return a2; }