[stubs] Optimize LoadGlobalViaContextStub and StoreGlobalViaContextStub.

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 b0f28d15dc82df874684142e954fc2a34ef0ef38..13a09c383e3e91210a970700144726968ce85725 100644
--- a/src/mips64/interface-descriptors-mips64.cc
+++ b/src/mips64/interface-descriptors-mips64.cc
@@ -36,12 +36,10 @@ const Register VectorStoreICDescriptor::VectorRegister() { return a3; }
 const Register StoreTransitionDescriptor::MapRegister() { return a3; }
 
 
-const Register LoadGlobalViaContextDescriptor::DepthRegister() { return a1; }
 const Register LoadGlobalViaContextDescriptor::SlotRegister() { return a2; }
 const Register LoadGlobalViaContextDescriptor::NameRegister() { return a3; }
 
 
-const Register StoreGlobalViaContextDescriptor::DepthRegister() { return a1; }
 const Register StoreGlobalViaContextDescriptor::SlotRegister() { return a2; }
 const Register StoreGlobalViaContextDescriptor::NameRegister() { return a3; }
 const Register StoreGlobalViaContextDescriptor::ValueRegister() { return a0; }