Enforce class definition ordering rules in v37 Dex files.

These new checks also reject classes extending or
implementing themselves directly or transitively within
a single Dex file.

Bug: 28812524
Bug: 28797012
Bug: 28685551
Bug: 27682580

Change-Id: I51c43f8b4b6a7abaade63682411e61f21767f5d4
diff --git a/runtime/dex_file.h b/runtime/dex_file.h
index ce7f62a..638821b 100644
--- a/runtime/dex_file.h
+++ b/runtime/dex_file.h
@@ -57,7 +57,11 @@
 // TODO: move all of the macro functionality into the DexCache class.
 class DexFile {
  public:
+  // First Dex format version supporting default methods.
   static const uint32_t kDefaultMethodsVersion = 37;
+  // First Dex format version enforcing class definition ordering rules.
+  static const uint32_t kClassDefinitionOrderEnforcedVersion = 37;
+
   static const uint8_t kDexMagic[];
   static constexpr size_t kNumDexVersions = 2;
   static constexpr size_t kDexVersionLen = 4;