Fix test-hashing after recent changes to string hashing.

src/mips/macro-assembler-mips.h

Index: src/mips/macro-assembler-mips.h
===================================================================
--- src/mips/macro-assembler-mips.h	(revision 10343)
+++ src/mips/macro-assembler-mips.h	(working copy)
@@ -53,13 +53,13 @@
 
 // Register aliases.
 // cp is assumed to be a callee saved register.
-const Register lithiumScratchReg = s3;  // Scratch register.
-const Register lithiumScratchReg2 = s4;  // Scratch register.
-const Register condReg = s5;  // Simulated (partial) condition code for mips.
-const Register roots = s6;  // Roots array pointer.
+const Register kLithiumScratchReg = s3;  // Scratch register.
+const Register kLithiumScratchReg2 = s4;  // Scratch register.
+const Register kCondReg = s5;  // Simulated (partial) condition code for mips.
+const Register kRootRegister = s6;  // Roots array pointer.
 const Register cp = s7;     // JavaScript context pointer.
 const Register fp = s8_fp;  // Alias for fp.
-const DoubleRegister lithiumScratchDouble = f30;  // Double scratch register.
+const DoubleRegister kLithiumScratchDouble = f30;  // Double scratch register.
 
 // Flags used for the AllocateInNewSpace functions.
 enum AllocationFlags {
@@ -789,6 +789,11 @@
                                     Register map,
                                     Register scratch);
 
+  void InitializeRootRegister() {
+    ExternalReference roots_array_start =
+        ExternalReference::roots_array_start(isolate());
+    li(kRootRegister, Operand(roots_array_start));
+  }
 
   // -------------------------------------------------------------------------
   // JavaScript invokes.