Revert unnecessary changes

Author: maxkoshevoi

src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationKeyComparer.cs

@@ -16,7 +16,7 @@ public class ConfigurationKeyComparer : IComparer<string>
         /// <summary>
         /// The default instance.
         /// </summary>
-        public static ConfigurationKeyComparer Instance { get; } = new();
+        public static ConfigurationKeyComparer Instance { get; } = new ConfigurationKeyComparer();
 
         /// <summary>A comparer delegate with the default instance.</summary>
         internal static Comparison<string> Comparison { get; } = Instance.Compare;

src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationProvider.cs

@@ -14,7 +14,7 @@ namespace Microsoft.Extensions.Configuration
     /// </summary>
     public abstract class ConfigurationProvider : IConfigurationProvider
     {
-        private ConfigurationReloadToken _reloadToken = new();
+        private ConfigurationReloadToken _reloadToken = new ConfigurationReloadToken();
 
         /// <summary>
         /// Initializes a new <see cref="IConfigurationProvider"/>

src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationReloadToken.cs

@@ -12,7 +12,7 @@ namespace Microsoft.Extensions.Configuration
     /// </summary>
     public class ConfigurationReloadToken : IChangeToken
     {
-        private CancellationTokenSource _cts = new();
+        private CancellationTokenSource _cts = new CancellationTokenSource();
 
         /// <summary>
         /// Indicates if this token will proactively raise callbacks. Callbacks are still guaranteed to be invoked, eventually.

src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationRoot.cs

@@ -15,7 +15,7 @@ public class ConfigurationRoot : IConfigurationRoot, IDisposable
     {
         private readonly IList<IConfigurationProvider> _providers;
         private readonly IList<IDisposable> _changeTokenRegistrations;
-        private ConfigurationReloadToken _changeToken = new();
+        private ConfigurationReloadToken _changeToken = new ConfigurationReloadToken();
 
         /// <summary>
         /// Initializes a Configuration root with a list of providers.

src/libraries/Microsoft.Extensions.Configuration/src/ConfigurationSection.cs

@@ -47,17 +47,30 @@ public ConfigurationSection(IConfigurationRoot root, string path)
         /// </summary>
         public string Key
         {
-            // Key is calculated lazily as last portion of Path
-            get => _key ??= ConfigurationPath.GetSectionKey(_path);
+            get
+            {
+                if (_key == null)
+                {
+                    // Key is calculated lazily as last portion of Path
+                    _key = ConfigurationPath.GetSectionKey(_path);
+                }
+                return _key;
+            }
         }
 
         /// <summary>
         /// Gets or sets the section value.
         /// </summary>
         public string? Value
         {
-            get => _root[Path];
-            set => _root[Path] = value;
+            get
+            {
+                return _root[Path];
+            }
+            set
+            {
+                _root[Path] = value;
+            }
         }
 
         /// <summary>
@@ -67,8 +80,14 @@ public string? Value
         /// <returns>The configuration value.</returns>
         public string? this[string key]
         {
-            get => _root[ConfigurationPath.Combine(Path, key)];
-            set => _root[ConfigurationPath.Combine(Path, key)] = value;
+            get
+            {
+                return _root[ConfigurationPath.Combine(Path, key)];
+            }
+            set
+            {
+                _root[ConfigurationPath.Combine(Path, key)] = value;
+            }
         }
 
         /// <summary>