aarch64: Add group suffixes to SVE intrinsics

aarch64: Add group suffixes to SVE intrinsics

The SME2 ACLE adds a new "group" suffix component to the naming
convention for SVE intrinsics.  This is also used in the new tuple
forms of the svreinterpret intrinsics.

This patch adds support for group suffixes and defines the
x2, x3 and x4 suffixes that are needed for the svreinterprets.

gcc/
	* config/aarch64/aarch64-sve-builtins-shapes.cc (build_one): Take
	a group suffix index parameter.
	(build_32_64, build_all): Update accordingly.  Iterate over all
	group suffixes.
	* config/aarch64/aarch64-sve-builtins-sve2.cc (svqrshl_impl::fold)
	(svqshl_impl::fold, svrshl_impl::fold): Update function_instance
	constructors.
	* config/aarch64/aarch64-sve-builtins.cc (group_suffixes): New array.
	(groups_none): New constant.
	(function_groups): Initialize the groups field.
	(function_instance::hash): Hash the group index.
	(function_builder::get_name): Add the group suffix.
	(function_builder::add_overloaded_functions): Iterate over all
	group suffixes.
	(function_resolver::lookup_form): Take a group suffix parameter.
	(function_resolver::resolve_to): Likewise.
	* config/aarch64/aarch64-sve-builtins.def (DEF_SVE_GROUP_SUFFIX): New
	macro.
	(x2, x3, x4): New group suffixes.
	* config/aarch64/aarch64-sve-builtins.h (group_suffix_index): New enum.
	(group_suffix_info): New structure.
	(function_group_info::groups): New member variable.
	(function_instance::group_suffix_id): Likewise.
	(group_suffixes): New array.
	(function_instance::operator==): Compare the group suffixes.
	(function_instance::group_suffix): New function.