* scripts/check_performance (CXX): Add -DNOTHREAD.
	* testsuite/performance/20_util/allocator/insert.cc: Integrate
	threaded tests from insert_insert.cc.  Tweak iterations,
	remove special cases.
	* testsuite/performance/20_util/allocator/insert_insert.cc:
	Make all tests single-threaded. Tweak iterations.
	* testsuite/performance/20_util/allocator/map_thread.cc:
	Tweak iterations.
	* testsuite/performance/20_util/allocator/producer_consumer.cc:
	Likewise.

From-SVN: r77388