[simulator] remove unused argument field for stop/breaks.

src/mips64/assembler-mips64.cc

Index: src/mips64/assembler-mips64.cc
diff --git a/src/mips64/assembler-mips64.cc b/src/mips64/assembler-mips64.cc
index b670058964e01959ba7fb15e2556a20a376b92c1..99c3c9b01a1bf8c652430c68ffdaa31c301d9ffe 100644
--- a/src/mips64/assembler-mips64.cc
+++ b/src/mips64/assembler-mips64.cc
@@ -2272,14 +2272,7 @@ void Assembler::stop(const char* msg, uint32_t code) {
   break_(0x54321);
 #else  // V8_HOST_ARCH_MIPS
   BlockTrampolinePoolFor(3);
-  // The Simulator will handle the stop instruction and get the message address.
-  // On MIPS stop() is just a special kind of break_().
   break_(code, true);
-  // Do not embed the message string address! We used to do this, but that
-  // made snapshots created from position-independent executable builds
-  // non-deterministic.
-  // TODO(yangguo): remove this field entirely.
-  nop();
 #endif
 }