Revert of MIPS: Use weak cells in map checks in polymorphic ICs. (patchset #1...

Revert of MIPS: Use weak cells in map checks in polymorphic ICs. (patchset #1 id:1 of https://codereview.chromium.org/767623003/)

Reason for revert:
Need to revert the ported CL:
https://codereview.chromium.org/771033003/

Original issue's description:
> MIPS: Use weak cells in map checks in polymorphic ICs.
>
> Port 45a36948
>
> Fix typo in the mips ports.
>
> BUG=

TBR=ulan@chromium.org,danno@chromium.org,akos.palfi@imgtec.com,balazs.kilvady@imgtec.com,gergely.kis@imgtec.com,dusan.milosavljevic@imgtec.com,paul.lind@imgtec.com
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/768303002

Cr-Commit-Position: refs/heads/master@{#25596}

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));
-  JumpIfSmi(value, miss);
+  JumpIfNotSmi(value, miss);
 }
 
 

src/mips64/macro-assembler-mips64.cc

@@ -4000,7 +4000,7 @@ void MacroAssembler::LoadWeakValue(Register value, Handle<WeakCell> cell,
                                    Label* miss) {
   li(value, Operand(cell));
   ld(value, FieldMemOperand(value, WeakCell::kValueOffset));
-  JumpIfSmi(value, miss);
+  JumpIfNotSmi(value, miss);
 }