Disable info messages by default for malloc debug.

Add a new option verbose for malloc debug that is not enabled by default.
This disables all of the info log messages. It turns out these log
messages can add a measurable amount of time and can change the boot up.

Bug: 129239269

Test: Adjusted unit tests pass.
Test: Verified no messages unless verbose option used.
Change-Id: I805cb7c8ecb44de88119574e59d784877cacc383
diff --git a/libc/bionic/malloc_common_dynamic.cpp b/libc/bionic/malloc_common_dynamic.cpp
index e12c247..3ccaed6 100644
--- a/libc/bionic/malloc_common_dynamic.cpp
+++ b/libc/bionic/malloc_common_dynamic.cpp
@@ -307,8 +307,6 @@
     atomic_store(&globals->current_dispatch_table, &globals->malloc_dispatch_table);
   }
 
-  info_log("%s: malloc %s enabled", getprogname(), prefix);
-
   // Use atexit to trigger the cleanup function. This avoids a problem
   // where another atexit function is used to cleanup allocated memory,
   // but the finalize function was already called. This particular error
@@ -316,7 +314,7 @@
   int ret_value = __cxa_atexit(MallocFiniImpl, nullptr, nullptr);
   if (ret_value != 0) {
     // We don't consider this a fatal error.
-    info_log("failed to set atexit cleanup function: %d", ret_value);
+    warning_log("failed to set atexit cleanup function: %d", ret_value);
   }
   return true;
 }