Update V8 to r3431 as required by WebKit r51976.

Change-Id: I567392c3f8c0a0d5201a4249611ac4ccf468cd5b
diff --git a/src/regexp-macro-assembler.cc b/src/regexp-macro-assembler.cc
index 0d00cee..9ae19d7 100644
--- a/src/regexp-macro-assembler.cc
+++ b/src/regexp-macro-assembler.cc
@@ -30,13 +30,7 @@
 #include "assembler.h"
 #include "regexp-stack.h"
 #include "regexp-macro-assembler.h"
-#if V8_TARGET_ARCH_ARM
-#include "arm/simulator-arm.h"
-#elif V8_TARGET_ARCH_IA32
-#include "ia32/simulator-ia32.h"
-#elif V8_TARGET_ARCH_X64
-#include "x64/simulator-x64.h"
-#endif
+#include "simulator.h"
 
 namespace v8 {
 namespace internal {
@@ -130,11 +124,6 @@
 
   if (StringShape(subject_ptr).IsCons()) {
     subject_ptr = ConsString::cast(subject_ptr)->first();
-  } else if (StringShape(subject_ptr).IsSliced()) {
-    SlicedString* slice = SlicedString::cast(subject_ptr);
-    start_offset += slice->start();
-    end_offset += slice->start();
-    subject_ptr = slice->buffer();
   }
   // Ensure that an underlying string has the same ascii-ness.
   ASSERT(subject_ptr->IsAsciiRepresentation() == is_ascii);