Address some FIXME comments (#4435)

* Address some FIXME comments

These comments have since been addressed by more modern code.
Remove them to reduce the clutter in the codebase.

* Remove 'dumb idea' from SimpleAllocator

4 year old code that was set never to run can probably be safely
deleted.

src/platform/esp32/SimpleAllocator.cpp

@@ -26,41 +26,3 @@ void *operator new(size_t size, SimpleAllocator &p)
 {
     return p.alloc(size);
 }
-
-#if 0 
-// This was a dumb idea, turn off for now
-
-SimpleAllocator *activeAllocator;
-
-AllocatorScope::AllocatorScope(SimpleAllocator &a)
-{
-    assert(!activeAllocator);
-    activeAllocator = &a;
-}
-
-AllocatorScope::~AllocatorScope()
-{
-    assert(activeAllocator);
-    activeAllocator = NULL;
-}
-
-/// Global new/delete, uses a simple allocator if it is in scope
-
-void *operator new(size_t sz) throw(std::bad_alloc)
-{
-    void *mem = activeAllocator ? activeAllocator->alloc(sz) : malloc(sz);
-    if (mem)
-        return mem;
-    else
-        throw std::bad_alloc();
-}
-
-void operator delete(void *ptr) throw()
-{
-    if (activeAllocator)
-        LOG_WARN("Leaking an active allocator object\n"); // We don't properly handle this yet
-    else
-        free(ptr);
-}
-
-#endif