Path.GetFullPath(string, string) uses case insensitive volume name comparison for drive rooted, relative paths (#97759)

* check root for drive relative paths case insensitive.

* Remove link

* apply feedback

---------

Co-authored-by: David Cantú <dacantu@microsoft.com>

Author: AnakinRaW

src/libraries/System.Private.CoreLib/src/System/IO/Path.Windows.cs

@@ -89,7 +89,7 @@ public static string GetFullPath(string path, string basePath)
                 // Drive relative paths
                 Debug.Assert(length == 2 || !PathInternal.IsDirectorySeparator(path[2]));
 
-                if (GetVolumeName(path.AsSpan()).EqualsOrdinal(GetVolumeName(basePath.AsSpan())))
+                if (GetVolumeName(path.AsSpan()).EqualsOrdinalIgnoreCase(GetVolumeName(basePath.AsSpan())))
                 {
                     // Matching root
                     // "C:Foo" and "C:\Bar" => "C:\Bar\Foo"
@@ -349,8 +349,8 @@ internal static int GetUncRootLength(ReadOnlySpan<char> path)
             if (!isDevice && path.Slice(0, 2).EqualsOrdinal(@"\\".AsSpan()))
                 return 2;
             else if (isDevice && path.Length >= 8
-                && (path.Slice(0, 8).EqualsOrdinal(PathInternal.UncExtendedPathPrefix.AsSpan())
-                || path.Slice(5, 4).EqualsOrdinal(@"UNC\".AsSpan())))
+                && (path.Slice(0, 8).EqualsOrdinalIgnoreCase(PathInternal.UncExtendedPathPrefix.AsSpan())
+                || path.Slice(5, 4).EqualsOrdinalIgnoreCase(@"UNC\".AsSpan())))
                 return 8;
 
             return -1;

src/libraries/System.Runtime/tests/System.Runtime.Extensions.Tests/System/IO/PathTests_Windows.cs

@@ -563,6 +563,8 @@ public void GetFullPath_CommonDevice_Windows(string path, string basePath, strin
             { @"C:tmp", @"C:\git\runtime", @"C:\git\runtime\tmp" },
             { @"C:", @"C:\git\runtime", @"C:\git\runtime" },
             { @"C", @"C:\git\runtime", @"C:\git\runtime\C" },
+            { @"c:", @"C:\git\runtime", @"C:\git\runtime" },
+            { @"C:tmp", @"c:\git\runtime", @"c:\git\runtime\tmp" },
 
             { @"Z:tmp\foo\..", @"C:\git\runtime", @"Z:\tmp" },
             { @"Z:tmp\foo\.", @"C:\git\runtime", @"Z:\tmp\foo" },