AAPT2: Add diff command

Adds the diff command and various small fixes to issues
discovered when diffing old AAPT built APKs with new AAPT2
built APKS.

Bug:22775504
Change-Id: I682a7fe1cf4b3efa7cbd5d18b333cf2d1046fe1b
diff --git a/tools/aapt2/ResourceUtils.cpp b/tools/aapt2/ResourceUtils.cpp
index 74c48b0..a0a7efc 100644
--- a/tools/aapt2/ResourceUtils.cpp
+++ b/tools/aapt2/ResourceUtils.cpp
@@ -289,7 +289,7 @@
 std::unique_ptr<BinaryPrimitive> tryParseFlagSymbol(const Attribute* flagAttr,
                                                     const StringPiece16& str) {
     android::Res_value flags = { };
-    flags.dataType = android::Res_value::TYPE_INT_DEC;
+    flags.dataType = android::Res_value::TYPE_INT_HEX;
     flags.data = 0u;
 
     if (util::trimWhitespace(str).empty()) {