Inline tcache functions

The functions tcache_get and tcache_put show up in profiles as they
are a critical part of the tcache code.  Inline them to give tcache
a 16% performance gain.  Since this improves multi-threaded cases
as well, it helps offset any potential performance loss due to adding
single-threaded fast paths.

	* malloc/malloc.c (tcache_put): Inline.
	(tcache_get): Inline.

(cherry-picked from commit e4dd4ace)