Move const declarations out of if in assembler-x64.cc (correcting linux64 bit compile error)

Review URL: http://codereview.chromium.org/1595028

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4414 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/assembler-x64.cc

@@ -1138,9 +1138,9 @@ void Assembler::j(Condition cc,
 void Assembler::jmp(Label* L) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
+  const int short_size = sizeof(int8_t);
+  const int long_size = sizeof(int32_t);
   if (L->is_bound()) {
-    const int short_size = sizeof(int8_t);
-    const int long_size = sizeof(int32_t);
     int offs = L->pos() - pc_offset() - 1;
     ASSERT(offs <= 0);
     if (is_int8(offs - short_size)) {