Implement a new mallctl operation that allows looking up the arena a
region of memory belongs to.

Instead of setting a fix value of 48 allowed VA bits,
we distiguish between LP64 and ILP32.

Testsuite result with LP64:
Test suite summary: pass: 13/13, skip: 0/13, fail: 0/13

Testsuit result with ILP32:
Test suite summary: pass: 13/13, skip: 0/13, fail: 0/13

Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

Related to https://github.com/jemalloc/jemalloc/issues/974

Background threads are created without holding the global background_thread
lock, which mean paused state is possible (and fine).

If no lazy lock or background thread is enabled, avoid dlsym pthread_create on
boot.

Previously, we would leak the extent and memory associated with a salvageable
portion of an extent that we were trying to split in three, in the case where
the first split attempt succeeded and the second failed.

Right now we always make our TLS use the initial-exec model if the compiler
supports it.  This change allows configure-time disabling of this setting, which
can be helpful when dynamically loading jemalloc is the only option.

When abort_conf is set, make sure we always error out at the end of the options
processing loop.

This dodges a warning emitted by the FreeBSD system gcc when compiling
libc for architectures which don't use clang as the system compiler.

Setting extent hooks can result in initializing an unused auto arena.  This is
useful to install extent hooks on auto arenas from the beginning.

Looking at the thread counts in our services, jemalloc's background thread
is useful, but mostly idle.  Add a config option to tune down the number of threads.

szind and slab bits are read on fast path, where compiler generated two memory
loads separately for them before this diff.  Manually operate on the bits to
avoid the extra memory load.

Add cast since read / write has unsigned return type on windows.

preserve_lru feature adds lots of complication, for little value.
Removing it means merged extents are re-added to the lru list, and may
take longer to madvise away than they otherwise would.

Canaries after removal seem flat for several services (no change).

1) make sure background thread 0 is always created; and 2) fix synchronization
between thread 0 and the control thread.

This reverts commit ae0f5d5c.

This completes the conversion; we now have only structured text output.

This was left over from a previous emitter conversion.  It didn't affect the
correctness of the output.