Prefer static_cast to reinterpret_cast (#4223)

* Change reinterpret_cast -> static_cast wherever possible
* Remove more unnecessary `const_cast`s.

reinterpret_casts should be avoided for the same reason as c-style casts - they don't do any type-checking. reinterpret_cast was mainly being used for down-casting in inheritance hierarchies but static_cast works just as well while also making sure that there is actually an inheritance relationship there.

src/OSSupport/File.cpp

@@ -285,7 +285,7 @@ int cFile::ReadRestOfFile(AString & a_Contents)
 
 	// HACK: This depends on the internal knowledge that AString's data() function returns the internal buffer directly
 	a_Contents.assign(DataSize, '\0');
-	return Read(reinterpret_cast<void *>(const_cast<char *>(a_Contents.data())), DataSize);
+	return Read(static_cast<void *>(const_cast<char *>(a_Contents.data())), DataSize);
 }
 
 

src/OSSupport/NetworkSingleton.cpp

@@ -173,7 +173,7 @@ void cNetworkSingleton::RunEventLoop(cNetworkSingleton * a_Self)
 
 void cNetworkSingleton::SignalizeStartup(evutil_socket_t a_Socket, short a_Events, void * a_Self)
 {
-	auto self = reinterpret_cast<cNetworkSingleton *>(a_Self);
+	auto self = static_cast<cNetworkSingleton *>(a_Self);
 	ASSERT(self != nullptr);
 	self->m_StartupEvent.Set();
 }

src/OSSupport/ServerHandleImpl.cpp

@@ -284,7 +284,7 @@ bool cServerHandleImpl::Listen(UInt16 a_Port)
 void cServerHandleImpl::Callback(evconnlistener * a_Listener, evutil_socket_t a_Socket, sockaddr * a_Addr, int a_Len, void * a_Self)
 {
 	// Cast to true self:
-	cServerHandleImpl * Self = reinterpret_cast<cServerHandleImpl *>(a_Self);
+	cServerHandleImpl * Self = static_cast<cServerHandleImpl *>(a_Self);
 	ASSERT(Self != nullptr);
 	ASSERT(Self->m_SelfPtr != nullptr);