Remove gMallocLeakZygoteChild.

Remove this global variable and change the setting of it to non-zero
to a call to android_mallopt.

In addition, change the initialize function to use pass a bool* instead of
int*.

Bug: 130028357

Test: Ran malloc_debug/malloc_hooks/perfetto tests.
Change-Id: I20d382bdeaaf38aac6b9dcabea5b3dfab3c945f6
Merged-In: I20d382bdeaaf38aac6b9dcabea5b3dfab3c945f6
(cherry picked from commit 5225b342f0810c027df3d09fbbcef4d324b19b93)