Give more meaningful names to two predicates.

compiler/goal_util.m:
    Rename generate_simple_call to generate_plain_call and
    generate_foreign_proc to generate_call_foreign_proc,
    since they generate plain_call and call_foreign_proc HLDS goals
    respectively. (And the latter most definitely does not generate
    foreign_procs themselves.)

    Rationalize the argument list of both predicates by putting
    related arguments together.

compiler/add_heap_ops.m:
compiler/add_trail_ops.m:
compiler/code_gen.m:
compiler/complexity.m:
compiler/dep_par_conj.m:
compiler/direct_arg_in_out.m:
compiler/format_call.m:
compiler/granularity.m:
compiler/lco.m:
compiler/modecheck_goal.m:
compiler/polymorphism_type_class_info.m:
compiler/polymorphism_type_info.m:
compiler/pragma_c_gen.m:
compiler/purity.m:
compiler/rbmm.region_transformation.m:
compiler/simplify_goal_call.m:
compiler/simplify_goal_scope.m:
compiler/simplify_goal_unify.m:
compiler/size_prof.m:
compiler/ssdebug.m:
compiler/stm_expand.m:
compiler/table_gen.m:
compiler/try_expand.m:
compiler/typecheck.m:
compiler/unify_proc.m:
    Conform to the changes above,

compiler/code_gen.m

@@ -313,7 +313,7 @@ generate_goal_expr(GoalExpr, GoalInfo, CodeModel, ForwardLiveVarsBeforeGoal,
         Lang = get_foreign_language(Attributes),
         (
             Lang = lang_c,
-            generate_foreign_proc_code(CodeModel, Attributes,
+            generate_code_for_foreign_proc(CodeModel, Attributes,
                 PredId, ProcId, Args, ExtraArgs, MaybeTraceRuntimeCond,
                 PragmaCode, GoalInfo, Code, !CI, !CLD)
         ;