Update clang and raise buffer size

Summary:
1. Fetch newest changes to ast exporter. Now we'll hash template instantiations inside declaration names if their string representation is too long (ie. 40 characters)
2. Increase biniou buffer to allow for long type names - they happen when dumping type raw name with long template instantiation (it's not hashed there yet, but infer doesn't use `ti_raw` field much

Reviewed By: dulmarod

Differential Revision: D3462743

fbshipit-source-id: 9152ae5

facebook-clang-plugins

@@ -1 +1 @@
-Subproject commit 05c9e572c2375be02a0c70de22ada0389f444774
+Subproject commit 3267da67afe81c99394f22226bad294922de0875

infer/src/clang/cMain.ml

@@ -17,7 +17,7 @@ module L = Logging
 
 open CFrontend_utils
 
-let buffer_len = 16384
+let buffer_len = 262143
 
 (* This function reads the json file in fname, validates it, and encoded in the AST data structure*)
 (* defined in Clang_ast_t.  *)