Change store buffer overflow check to not rely on the store buffer being (2*Size) aligned.

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 2ddfa4aeec4bf9d5caa30408d1520e503c7e9097..5fdc0b64b7cd038f5f996fc7ff5d745cec974644 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -482,12 +482,12 @@ void MacroAssembler::RememberedSetHelper(Register object,  // For debug tests.
   sw(scratch, MemOperand(t8));
   // Call stub on end of buffer.
   // Check for end of buffer.
-  And(t8, scratch, Operand(StoreBuffer::kStoreBufferOverflowBit));
+  And(t8, scratch, Operand(StoreBuffer::kStoreBufferMask));
   if (and_then == kFallThroughAtEnd) {
-    Branch(&done, eq, t8, Operand(zero_reg));
+    Branch(&done, ne, t8, Operand(zero_reg));
   } else {
     DCHECK(and_then == kReturnAtEnd);
-    Ret(eq, t8, Operand(zero_reg));
+    Ret(ne, t8, Operand(zero_reg));
   }
   push(ra);
   StoreBufferOverflowStub store_buffer_overflow(isolate(), fp_mode);