Replace ArrayList with a fixed-size array to reduce allocations

Author: h3xds1nz

src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/InputLanguageManager.cs

@@ -287,7 +287,7 @@ public IEnumerable AvailableInputLanguages
                     return null;
                 }
 
-                return (IEnumerable)_source.InputLanguageList;
+                return _source.InputLanguageList;
             }
         }
 

src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/InputLanguageSource.cs

@@ -130,11 +130,8 @@ public IEnumerable InputLanguageList
                 EnsureInputProcessorProfile();
 
                 if (_ipp == null)
-                {
-                    ArrayList al = new ArrayList();
-                    al.Add(CurrentInputLanguage);
-                    return al;
-                }
+                    return new CultureInfo[1] { CurrentInputLanguage };
+
                 return _ipp.InputLanguageList;
              }
         }