Userland: Fix unnecessary heap allocation of singleton objects

In order to avoid having multiple instances, we were keeping a pointer
to these singleton objects and only allocating them when it was null.

We have `__cxa_guard_{acquire,release}` in the userland, so there's no
need to do this dance, as the compiler will ensure that the constructors
are only called once.

Userland/Libraries/LibGfx/FontDatabase.cpp

@@ -15,13 +15,10 @@
 
 namespace Gfx {
 
-static FontDatabase* s_the;
-
 FontDatabase& FontDatabase::the()
 {
-    if (!s_the)
-        s_the = new FontDatabase;
-    return *s_the;
+    static FontDatabase s_the;
+    return s_the;
 }
 
 static RefPtr<Font> s_default_font;