[llvm-profgen] ProfiledBinary::load - use cast<> instead of dyn_cast<> to avoid dereference of nullptr

The pointer is always dereferenced immediately, so assert the cast is correct instead of returning nullptr

llvm/tools/llvm-profgen/ProfiledBinary.cpp

@@ -206,7 +206,7 @@ void ProfiledBinary::load() {
   decodePseudoProbe(Obj);
 
   // Load debug info of subprograms from DWARF section.
-  loadSymbolsFromDWARF(*dyn_cast<ObjectFile>(&Binary));
+  loadSymbolsFromDWARF(*cast<ObjectFile>(&Binary));
 
   // Disassemble the text sections.
   disassemble(Obj);