PR libstdc++/85749 constrain seed sequences for random number engines

PR libstdc++/85749 constrain seed sequences for random number engines

Constrain constructors and member functions of random number engines so
that functions taking seed sequences can only be called with types that
meet the seed sequence requirements.

	PR libstdc++/85749
	* include/bits/random.h (__detail::__is_seed_seq): New SFINAE helper.
	(linear_congruential_engine, mersenne_twister_engine)
	(subtract_with_carry_engine, discard_block_engine)
	(independent_bits_engine, shuffle_order_engine): Use __is_seed_seq to
	constrain function templates taking seed sequences.
	* include/bits/random.tcc (linear_congruential_engine::seed(_Sseq&))
	(mersenne_twister_engine::seed(_Sseq&))
	(subtract_with_carry_engine::seed(_Sseq&)): Change return types to
	match declarations.
	* include/ext/random (simd_fast_mersenne_twister_engine): Use
	__is_seed_seq to constrain function templates taking seed sequences.
	* include/ext/random.tcc (simd_fast_mersenne_twister_engine::seed):
	Change return type to match declaration.
	* testsuite/26_numerics/random/discard_block_engine/cons/seed_seq2.cc:
	New.
	* testsuite/26_numerics/random/independent_bits_engine/cons/
	seed_seq2.cc: New.
	* testsuite/26_numerics/random/linear_congruential_engine/cons/
	seed_seq2.cc: New.
	* testsuite/26_numerics/random/mersenne_twister_engine/cons/
	seed_seq2.cc: New.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.
	* testsuite/26_numerics/random/shuffle_order_engine/cons/seed_seq2.cc:
	New.
	* testsuite/26_numerics/random/subtract_with_carry_engine/cons/
	seed_seq2.cc: New.
	* testsuite/ext/random/simd_fast_mersenne_twister_engine/cons/
	seed_seq2.cc: New.

From-SVN: r260263