Reorder unit test headers for consistency.

Author: Sonny Martin

unit/goto-programs/goto_program_declaration.cpp

@@ -8,10 +8,10 @@ Author: Diffblue Ltd.
 
 #include <testing-utils/use_catch.h>
 
-#include <goto-programs/goto_function.h>
-
 #include <util/arith_tools.h>
 
+#include <goto-programs/goto_function.h>
+
 SCENARIO(
   "Validation of well-formed declaration codes",
   "[core][goto-programs][validate]")

unit/goto-programs/goto_program_goto_target.cpp

@@ -8,10 +8,10 @@ Author: Diffblue Ltd.
 
 #include <testing-utils/use_catch.h>
 
-#include <goto-programs/goto_function.h>
-
 #include <util/arith_tools.h>
 
+#include <goto-programs/goto_function.h>
+
 SCENARIO(
   "Validation of well-formed goto codes",
   "[core][goto-programs][validate]")

unit/goto-programs/goto_program_validate.cpp

@@ -14,14 +14,14 @@
 
 #include <testing-utils/message.h>
 
-#include <goto-programs/goto_convert_functions.h>
-#include <goto-programs/validate_goto_model.h>
-
 #include <util/arith_tools.h>
 #include <util/c_types.h>
 #include <util/std_code.h>
 #include <util/validate.h>
 
+#include <goto-programs/goto_convert_functions.h>
+#include <goto-programs/validate_goto_model.h>
+
 SCENARIO("Validation of a goto program", "[core][goto-programs][validate]")
 {
   goto_modelt goto_model;