Fix a few assertions that were found when using debug CRT

src/openrct2-ui/drawing/engines/HardwareDisplayDrawingEngine.cpp

@@ -68,9 +68,15 @@ public:
     }
 
     ~HardwareDisplayDrawingEngine() override
+    {
+        if (_screenTexture != nullptr)
         {
             SDL_DestroyTexture(_screenTexture);
+        }
+        if (_scaledScreenTexture != nullptr)
+        {
             SDL_DestroyTexture(_scaledScreenTexture);
+        }
         SDL_FreeFormat(_screenTextureFormat);
         SDL_DestroyRenderer(_sdlRenderer);
     }
@@ -92,8 +98,11 @@ public:
     }
 
     void Resize(uint32 width, uint32 height) override
+    {
+        if (_screenTexture != nullptr)
         {
             SDL_DestroyTexture(_screenTexture);
+        }
         SDL_FreeFormat(_screenTextureFormat);
 
         SDL_RendererInfo rendererInfo = {};
@@ -127,8 +136,11 @@ public:
         }
 
         if (smoothNN)
+        {
+            if (_scaledScreenTexture != nullptr)
             {
                 SDL_DestroyTexture(_scaledScreenTexture);
+            }
 
             char scaleQualityBuffer[4];
             snprintf(scaleQualityBuffer, sizeof(scaleQualityBuffer), "%u", scaleQuality);

src/openrct2-ui/windows/ServerList.cpp

@@ -567,7 +567,7 @@ static bool server_compare(const server_entry &a, const server_entry &b)
     }
 
     // Then by name
-    return String::Compare(a.name, b.name, true) <= 0;
+    return String::Compare(a.name, b.name, true) < 0;
 }
 
 static void sort_servers()

src/openrct2/object/StringTable.cpp

@@ -44,7 +44,7 @@ static bool StringIsBlank(const utf8 * str)
 {
     for (auto ch = str; *ch != '\0'; ch++)
     {
-        if (!isblank(*ch))
+        if (!isblank((uint8)*ch))
         {
             return false;
         }