Move int rounding folds to match.pd

Move int rounding folds to match.pd

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* builtins.c (do_real_to_int_conversion): New function.
	(fold_fixed_mathfn, fold_builtin_int_roundingfn): Delete.
	(fold_builtin_1): Handle constant {i,l,ll}{ceil,floor,round}{f,,l}
	arguments here.
	* match.pd: Add rules previously handled by fold_fixed_mathfn
	and fold_builtin_int_roundingfn.

gcc/testsuite/
	* gcc.dg/torture/builtin-minmax-1.c: Don't run at -O0.

From-SVN: r229311