Fix memory leak

A long running heap profile of the Scilla process from a ZQ2 node
showed growing memory usage. The allocations were mainly happening
in `add_comment`. I'm not sure why/where we retain the reference
to this forever, but I did see that the only user of `get_comments`
was `scilla-fmt`, which we are not using.

Therefore, I did the easy fix and removed `scilla-fmt`.

Author: JamesHinshelwood

src/base/FrontEndParser.ml

@@ -147,6 +147,4 @@ module ScillaFrontEndParser (Literal : ScillaLiteral) = struct
     let open Result.Let_syntax in
     let%bind cmod = parse_string Parser.Incremental.cmodule s in
     pure @@ disambiguate_calls cmod
-
-  let get_comments () = Lexer.get_comments ()
 end

src/base/ScillaLexer.mll

@@ -28,12 +28,6 @@ module MkLexer (S : ParserUtil.Syn) = struct
   open Parser
 
   exception Error of string
-
-  let comments = ref []
-  let add_comment start_p s =
-    let loc = ErrorUtils.toLoc start_p in
-    comments := (loc, s) :: !comments
-  let get_comments () = List.rev !comments
 }
 
 let digit = ['0'-'9']
@@ -157,8 +151,7 @@ and comment buf braces =
   parse
   | "(*"      { comment buf (lexbuf.lex_curr_p::braces) lexbuf }
   | "*)"      { match braces with
-                  p::[] -> add_comment p (Buffer.contents buf);
-                           read lexbuf
+                  p::[] -> read lexbuf
                 | _ -> comment buf (List.tl_exn braces) lexbuf }
   | newline   { new_line lexbuf;
                 Buffer.add_char buf '\n';

src/runners/dune

@@ -1,11 +1,11 @@
 (executables
  (names scilla_runner scilla_checker scilla_server
-   disambiguate_state_json scilla_fmt scilla_merger scilla_server_http)
+   disambiguate_state_json scilla_merger scilla_server_http)
  (public_names scilla-runner scilla-checker
-   scilla-server disambiguate_state_json scilla-fmt scilla-merger scilla-server-http)
+   scilla-server disambiguate_state_json scilla-merger scilla-server-http)
  (package scilla)
  (modules scilla_runner scilla_checker scilla_server
-   disambiguate_state_json scilla_fmt scilla_merger scilla_server_http)
+   disambiguate_state_json scilla_merger scilla_server_http)
  (libraries core core_unix.command_unix angstrom yojson cryptokit fileutils
    scilla_base scilla_eval scilla_server_lib scilla_crypto scilla_format
    scilla_merge cmdliner opium memtrace)