clean up the a few cases where HAVE_STRUCT_MALLINFO was not renamed

With the introduction of `TCMALLOC_HAVE_STRUCT_MALLINFO`, tcmalloc uniformly
uses this macro to ensure portability to libc implementations which do not
provide the SVID `mallopt` interfaces.  Port the last few stragglers to the new
macro.

PiperOrigin-RevId: 391131502
Change-Id: Ic3a1b40196f197a9c052333e904d549469af3bd6

Author: compnerd

tcmalloc/libc_override_redefine.h

@@ -67,7 +67,7 @@ int posix_memalign(void** r, size_t a, size_t s) noexcept {
 }
 void malloc_stats(void) noexcept { TCMallocInternalMallocStats(); }
 int mallopt(int cmd, int v) noexcept { return TCMallocInternalMallOpt(cmd, v); }
-#ifdef HAVE_STRUCT_MALLINFO
+#ifdef TCMALLOC_HAVE_STRUCT_MALLINFO
 struct mallinfo mallinfo(void) noexcept {
   return TCMallocInternalMallocInfo();
 }