Avoid creation of temporary strings where possible (#11380)

Author: Erarndt

src/Build/BackEnd/Shared/BuildRequestConfiguration.cs

@@ -299,7 +299,11 @@ public bool IsTraversal
             {
                 if (!_isTraversalProject.HasValue)
                 {
-                    if (String.Equals(Path.GetFileName(ProjectFullPath), "dirs.proj", StringComparison.OrdinalIgnoreCase))
+#if NET471_OR_GREATER
+                    if (MemoryExtensions.Equals(Microsoft.IO.Path.GetFileName(ProjectFullPath.AsSpan()), "dirs.proj".AsSpan(), StringComparison.OrdinalIgnoreCase))
+#else
+                    if (MemoryExtensions.Equals(Path.GetFileName(ProjectFullPath.AsSpan()), "dirs.proj", StringComparison.OrdinalIgnoreCase))
+#endif
                     {
                         // dirs.proj are assumed to be traversals
                         _isTraversalProject = true;

src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs

@@ -1223,15 +1223,18 @@ private void EnsureParameterInitialized(TaskPropertyInfo parameter, Lookup looku
 
             string taskAndParameterName = _taskName + "_" + parameter.Name;
             string key = "DisableLogTaskParameter_" + taskAndParameterName;
-            string metadataKey = "DisableLogTaskParameterItemMetadata_" + taskAndParameterName;
 
             if (string.Equals(lookup.GetProperty(key)?.EvaluatedValue, "true", StringComparison.OrdinalIgnoreCase))
             {
                 parameter.Log = false;
             }
-            else if (string.Equals(lookup.GetProperty(metadataKey)?.EvaluatedValue, "true", StringComparison.OrdinalIgnoreCase))
+            else
             {
-                parameter.LogItemMetadata = false;
+                string metadataKey = "DisableLogTaskParameterItemMetadata_" + taskAndParameterName;
+                if (string.Equals(lookup.GetProperty(metadataKey)?.EvaluatedValue, "true", StringComparison.OrdinalIgnoreCase))
+                {
+                    parameter.LogItemMetadata = false;
+                }
             }
         }
 

src/Tasks/SystemState.cs

@@ -456,9 +456,7 @@ private AssemblyNameExtension GetAssemblyName(string path)
             // then we can short-circuit the File IO involved with GetAssemblyName()
             if (redistList != null)
             {
-                string extension = Path.GetExtension(path);
-
-                if (string.Equals(extension, ".dll", StringComparison.OrdinalIgnoreCase))
+                if (!string.IsNullOrEmpty(path) && path.EndsWith(".dll", StringComparison.OrdinalIgnoreCase))
                 {
                     IEnumerable<AssemblyEntry> assemblyNames = redistList.FindAssemblyNameFromSimpleName(
                             Path.GetFileNameWithoutExtension(path));