Profiler: Symbolicate addresses in non-PIE ELF objects

This is a little bit messy, but basically if an ELF object is non-PIE,
we have to account for the executable mapping being at a hard-coded
offset and subtract that when doing symbolication.

There's probably a nicer way to solve this, I just hacked this together
so we can see "cc1plus" and friends in profiles. :^)

Userland/DevTools/Profiler/Profile.h

@@ -59,7 +59,10 @@ public:
         FlatPtr base;
         size_t size;
         String name;
+        FlatPtr text_base;
         MappedObject* object { nullptr };
+
+        String symbolicate(FlatPtr, u32* offset) const;
     };
 
     const Library* library_containing(FlatPtr) const;