Fix line number calculation that deviates from old Dalvik.

In old Dalvik, adjopcode was declared as int instead of uint8. And
it's declared in different scope.
Pass the art-target tests and art-host tests.

Change-Id: Ie65c16a43ca32f1acf425a740bebc02f005f9011
diff --git a/src/dex_file.cc b/src/dex_file.cc
index a11744d..0a18f11 100644
--- a/src/dex_file.cc
+++ b/src/dex_file.cc
@@ -675,10 +675,8 @@
 
   for (;;)  {
     uint8_t opcode = *stream++;
-    uint8_t adjopcode = opcode - DBG_FIRST_SPECIAL;
     uint16_t reg;
 
-
     switch (opcode) {
       case DBG_END_SEQUENCE:
         return;
@@ -755,7 +753,9 @@
       case DBG_SET_FILE:
         break;
 
-      default:
+      default: {
+        int adjopcode = opcode - DBG_FIRST_SPECIAL;
+
         address += adjopcode / DBG_LINE_RANGE;
         line += DBG_LINE_BASE + (adjopcode % DBG_LINE_RANGE);
 
@@ -766,6 +766,7 @@
           }
         }
         break;
+      }
     }
   }
 }