Add sized-delete size-checking functionality.

The existing checks are good at finding such issues (on tcache flush), but not
so good at pinpointing them.  Debug mode can find them, but sometimes debug mode
slows down a program so much that hard-to-hit bugs can take a long time to
crash.

This commit adds functionality to keep programs mostly on their fast paths,
while also checking every sized delete argument they get.

include/jemalloc/internal/jemalloc_internal_defs.h.in

@@ -373,4 +373,7 @@
 /* Performs additional safety checks when defined. */
 #undef JEMALLOC_OPT_SAFETY_CHECKS
 
+/* Performs additional size checks when defined. */
+#undef JEMALLOC_OPT_SIZE_CHECKS
+
 #endif /* JEMALLOC_INTERNAL_DEFS_H_ */

include/jemalloc/internal/jemalloc_preamble.h.in

@@ -180,6 +180,19 @@ static const bool config_opt_safety_checks =
 #endif
     ;
 
+/*
+ * Extra debugging of sized deallocations too onerous to be included in the
+ * general safety checks.
+ */
+static const bool config_opt_size_checks =
+#if defined(JEMALLOC_OPT_SIZE_CHECKS) || defined(JEMALLOC_OPT_SAFETY_CHECKS) \
+    || defined(JEMALLOC_DEBUG)
+    true
+#else
+    false
+#endif
+    ;
+
 #if defined(_WIN32) || defined(JEMALLOC_HAVE_SCHED_GETCPU)
 /* Currently percpu_arena depends on sched_getcpu. */
 #define JEMALLOC_PERCPU_ARENA