use xxhash output type

Author: mjain-jump

flatbuffers/context.fbs

@@ -10,6 +10,10 @@ struct Signature {
   signature:[ubyte:64];
 }
 
+struct XXHash {
+  hash:[ubyte:8];
+}
+
 struct Hash {
   hash:[ubyte:32];
 }

flatbuffers/elf.fbs

@@ -13,11 +13,11 @@ table ELFLoaderCtx {
 
 table ELFLoaderEffects {
   err_code:ubyte;
-  rodata_hash:ulong;
+  rodata_hash:XXHash;
   text_cnt:ulong;
   text_off:ulong;
   entry_pc:ulong;
-  calldests_hash:ulong;
+  calldests_hash:XXHash;
 }
 
 table ELFLoaderFixture {