error: SDL's allocators now call SDL_OutOfMemory on error.

This means the allocator's caller doesn't need to use SDL_OutOfMemory directly
if the allocation fails.

This applies to the usual allocators: SDL_malloc, SDL_calloc, SDL_realloc
(all of these regardless of if the app supplied a custom allocator or we're
using system malloc() or an internal copy of dlmalloc under the hood),
SDL_aligned_alloc, SDL_small_alloc, SDL_strdup, SDL_asprintf, SDL_wcsdup...
probably others. If it returns something you can pass to SDL_free, it should
work.

The caller might still need to use SDL_OutOfMemory if something that wasn't
SDL allocated the memory: operator new in C++ code, Objective-C's alloc
message, win32 GlobalAlloc, etc.

Fixes #8642.

test/testutils.c

@@ -36,7 +36,6 @@ GetNearbyFilename(const char *file)
 
         if (!path) {
             SDL_free(base);
-            SDL_OutOfMemory();
             return NULL;
         }
 
@@ -53,11 +52,7 @@ GetNearbyFilename(const char *file)
         SDL_free(path);
     }
 
-    path = SDL_strdup(file);
-    if (!path) {
-        SDL_OutOfMemory();
-    }
-    return path;
+    return SDL_strdup(file);
 }
 
 /**
@@ -73,16 +68,9 @@ char *
 GetResourceFilename(const char *user_specified, const char *def)
 {
     if (user_specified) {
-        char *ret = SDL_strdup(user_specified);
-
-        if (!ret) {
-            SDL_OutOfMemory();
-        }
-
-        return ret;
-    } else {
-        return GetNearbyFilename(def);
+        return SDL_strdup(user_specified);
     }
+    return GetNearbyFilename(def);
 }
 
 /**