MIPS: Use weak cells in map checks in polymorphic ICs.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 2a5ea1adc5314f4ff6ba421f02f8014e5134bb8e..b2f60c5d2a09749cdedcbb862495d6ac1c01c3db 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -4033,7 +4033,7 @@ void MacroAssembler::LoadWeakValue(Register value, Handle<WeakCell> cell,
                                    Label* miss) {
   li(value, Operand(cell));
   lw(value, FieldMemOperand(value, WeakCell::kValueOffset));
-  JumpIfNotSmi(value, miss);
+  JumpIfSmi(value, miss);
 }