Rename iterate to malloc_iterate internally.

I have no idea why I used the iterate name internally which is
completely unlike every other function name. Change this to match
everyone else so that it's now malloc_iterate everywhere.

This is probably the last chance to change this before mainline
modules begin, so make everything consistent.

Test: Compiles, unit tests passes.
Change-Id: I56d293377fa0fe1a3dc3dd85d6432f877cc2003c
diff --git a/libc/private/bionic_malloc_dispatch.h b/libc/private/bionic_malloc_dispatch.h
index aea3a1c..52d8573 100644
--- a/libc/private/bionic_malloc_dispatch.h
+++ b/libc/private/bionic_malloc_dispatch.h
@@ -70,7 +70,7 @@
 #if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
   MallocValloc valloc;
 #endif
-  MallocIterate iterate;
+  MallocIterate malloc_iterate;
   MallocMallocDisable malloc_disable;
   MallocMallocEnable malloc_enable;
   MallocMallopt mallopt;