Bug #30488061: MAKE DOXYGEN SHOULD NOT SORT LINES

There is a command called "make doxygen" (or, equivalently, "ninja doxygen")
that runs Doxygen and does some filtering. However, in order to deduplicate
lines, it also sorts them. This causes issues with multiline warnings, such as:

sql/sql_executor.cc:1926: warning: The following parameters of GetIteratorForDerivedTable(THD *thd, QEP_TAB *qep_tab) are not documented:
  parameter 'thd'
  parameter 'qep_tab'

which then get split apart, making them hard to read. Thus, stop sorting them;
there are typically no duplicates anyway.

Change-Id: I4c0d5b94247d1df1d5a16beba83c65cfce5e3019

run_doxygen.cmake

@@ -1,4 +1,4 @@
-# Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License, version 2.0,
@@ -48,13 +48,11 @@ FOREACH(LINE ${IGNORE_FILE_LINES})
   ENDIF()
 ENDFOREACH()
 
-# Convert ERROR_FILE contents to a list of lines, and sort it
+# Convert ERROR_FILE contents to a list of lines
 FILE(READ ${ERROR_FILE} ERROR_FILE_CONTENTS)
 IF(ERROR_FILE_CONTENTS)
   STRING(REPLACE ";" "\\\\;" ERROR_FILE_CONTENTS ${ERROR_FILE_CONTENTS})
   STRING(REPLACE "\n" ";" ERROR_FILE_LINES ${ERROR_FILE_CONTENTS})
-  LIST(SORT ERROR_FILE_LINES)
-  LIST(REMOVE_DUPLICATES ERROR_FILE_LINES)
 ENDIF()
 
 FILE(REMOVE ${TOFIX_FILE})