Fix infinite purging loop in HPA

As reported in #2449, under certain circumstances it's possible to get
stuck in an infinite loop attempting to purge from the HPA. We now
handle this by validating the HPA settings at the end of
configuration parsing and either normalizing them or aborting depending on
if `abort_conf` is set.

include/jemalloc/internal/jemalloc_internal_externs.h

@@ -25,6 +25,7 @@ extern bool opt_junk_alloc;
 extern bool opt_junk_free;
 extern void (*JET_MUTABLE junk_free_callback)(void *ptr, size_t size);
 extern void (*JET_MUTABLE junk_alloc_callback)(void *ptr, size_t size);
+extern void (*JET_MUTABLE invalid_conf_abort)(void);
 extern bool opt_utrace;
 extern bool opt_xmalloc;
 extern bool opt_experimental_infallible_new;