tdf#120703 (PVS): redundant nullptr check

V668 There is no sense in testing the 'pResult' pointer against null, as
     the memory was allocated using the 'new' operator. The exception will
     be generated in the case of memory allocation error.

Change-Id: I8c80df7100e6cdf6c3c51957e3bef3c8a9f30732
Reviewed-on: https://gerrit.libreoffice.org/62137
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

sd/source/ui/slidesorter/cache/SlsPageCacheManager.cxx

@@ -215,8 +215,7 @@ std::shared_ptr<BitmapCache> PageCacheManager::GetCache (
     Recycle(pResult, pDocument,rPreviewSize);
 
     // Put the new (or old) cache into the container.
-    if (pResult != nullptr)
-        mpPageCaches->emplace(aKey, pResult);
+    mpPageCaches->emplace(aKey, pResult);
 
     return pResult;
 }