Fail gracefully if we get unparsable JSON

We seem to sometimes not read enough bytes from the Sorbet output, which
ends up causing us to get an error from the JSON parser. While we
investigate and fix that root cause, we might as well gracefully handle
JSON parsing errors.

lib/tapioca/static/symbol_table_parser.rb

@@ -16,6 +16,8 @@ def self.parse_json(json_string)
         parser = SymbolTableParser.new
         parser.parse_object(obj)
         parser.symbols
+      rescue JSON::ParserError
+        Set.new
       end
 
       sig { returns(T::Set[String]) }