Simplify and fix code aging.

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 5a0bb3066b490860cbeffe65eaf478a1b07d0e33..b8b3ea159e8bb7071377acbc4e309d89e79934d6 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -158,14 +158,11 @@ void FullCodeGenerator::Generate() {
   // function calls.
   if (!info->is_classic_mode() || info->is_native()) {
     Label ok;
-    Label begin;
-    __ bind(&begin);
     __ Branch(&ok, eq, t1, Operand(zero_reg));
     int receiver_offset = info->scope()->num_parameters() * kPointerSize;
     __ LoadRoot(a2, Heap::kUndefinedValueRootIndex);
     __ sw(a2, MemOperand(sp, receiver_offset));
     __ bind(&ok);
-    ASSERT_EQ(kSizeOfFullCodegenStrictModePrologue, ok.pos() - begin.pos());
   }
 
   // Open a frame scope to indicate that there is a frame on the stack.  The
@@ -175,6 +172,7 @@ void FullCodeGenerator::Generate() {
 
   int locals_count = info->scope()->num_stack_slots();
 
+  info->set_prologue_offset(masm_->pc_offset());
   // The following three instructions must remain together and unmodified for
   // code aging to work properly.
   __ Push(ra, fp, cp, a1);