Make "disable memory mitigations" and "set heap tagging level" more available.

These were only available internally via android_mallopt(), but they're
likely to be needed by more code in future, so move them into mallopt().

This change leaves the android_mallopt() options for now, but I plan on
coming back to remove them after I've switched the handful of callers
over to mallopt() instead.

Bug: http://b/135772972
Test: treehugger
Change-Id: Ia154614069a7623c6aca85975a91e6a156f04759
diff --git a/libc/bionic/memory_mitigation_state.cpp b/libc/bionic/memory_mitigation_state.cpp
index 4761d88..b262f86 100644
--- a/libc/bionic/memory_mitigation_state.cpp
+++ b/libc/bionic/memory_mitigation_state.cpp
@@ -47,8 +47,8 @@
 
 extern "C" void scudo_malloc_set_zero_contents(int zero_contents);
 
-bool DisableMemoryMitigations(void* arg, size_t arg_size) {
-  if (arg || arg_size) {
+bool DisableMemoryMitigations(int arg) {
+  if (arg != 0) {
     return false;
   }
 
@@ -61,7 +61,7 @@
   HeapTaggingLevel current_level = GetHeapTaggingLevel();
   if (current_level != M_HEAP_TAGGING_LEVEL_NONE && current_level != M_HEAP_TAGGING_LEVEL_TBI) {
     HeapTaggingLevel level = M_HEAP_TAGGING_LEVEL_NONE;
-    SetHeapTaggingLevel(reinterpret_cast<void*>(&level), sizeof(level));
+    SetHeapTaggingLevel(level);
   }
 
   return true;