Avoid a LINQ usage in tensor extensions (#109405)

* Avoid a LINQ usage in tensor extensions

This one, in particular, was causing an error with upcoming compiler changes:

    /vmr/src/runtime/src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/QCallHandles.cs(39,26): warning CS9265: Field 'ByteRef._ref' is never ref-assigned to, and will always have its default value (null reference) [/vmr/src/runtime/src/coreclr/System.Private.CoreLib/System.Private.CoreLib.csproj]
    /vmr/src/runtime/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs(1168,30): warning CS8619: Nullability of reference types in value of type 'string[]' doesn't match target type 'Span<string?>'. [/vmr/src/runtime/src/libraries/System.Net.Http/src/System.Net.Http.csproj::TargetFramework=net10.0-linux]
    /vmr/src/runtime/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs(1208,42): warning CS8620: Argument of type 'string[]' cannot be used for parameter 'values' of type 'Span<string?>' in 'void HttpHeaders.ReadStoreValues<object?>(Span<string?> values, object? storeValue, HttpHeaderParser? parser, ref int currentIndex)' due to differences in the nullability of reference types. [/vmr/src/runtime/src/libraries/System.Net.Http/src/System.Net.Http.csproj::TargetFramework=net10.0-linux]
    /vmr/src/runtime/src/libraries/System.Net.Http/src/System/Net/Http/Headers/HttpHeaders.cs(1209,42): warning CS8620: Argument of type 'string[]' cannot be used for parameter 'values' of type 'Span<string?>' in 'void HttpHeaders.ReadStoreValues<string?>(Span<string?> values, object? storeValue, HttpHeaderParser? parser, ref int currentIndex)' due to differences in the nullability of reference types. [/vmr/src/runtime/src/libraries/System.Net.Http/src/System.Net.Http.csproj::TargetFramework=net10.0-linux]
    /vmr/src/runtime/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorExtensions.cs(2661,56): error CS0023: Operator '.' cannot be applied to operand of type 'void' [/vmr/src/runtime/src/libraries/System.Numerics.Tensors/src/System.Numerics.Tensors.csproj::TargetFramework=net10.0]
        4 Warning(s)
        1 Error(s)

* Fold into one loop

* Remove unnecessary wrapper

Author: am11

src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorExtensions.cs

@@ -2658,8 +2658,14 @@ public static Tensor<T> PermuteDimensions<T>(this Tensor<T> tensor, params ReadO
 
                 if (dimensions.IsEmpty)
                 {
-                    lengths = tensor._lengths.Reverse().ToArray();
-                    permutation = Enumerable.Range(0, tensor.Rank).Reverse().ToArray();
+                    int[] tempPermutation = new int[tensor.Rank];
+                    for (int i = 0; i < tensor.Rank; i++)
+                    {
+                        lengths[i] = tensor._lengths[tensor.Rank - 1 - i];
+                        tempPermutation[i] = tensor.Rank - 1 - i;
+                    }
+
+                    permutation = tempPermutation;
                 }
                 else
                 {