remove IsAbs validation on local volume

use MakeAbsolutePath to convert path in Windows

fix test error: allow relative path for local volume

fix comments

fix comments and add windows unit tests

pkg/apis/core/validation/validation_test.go

@@ -521,8 +521,8 @@ func TestValidateLocalVolumes(t *testing.T) {
 			volume: testVolume("foo", "",
 				testLocalVolume("/foo/..", simpleVolumeNodeAffinity("foo", "bar"))),
 		},
-		"invalid-local-volume-relative-path": {
-			isExpectedFailure: true,
+		"valid-local-volume-relative-path": {
+			isExpectedFailure: false,
 			volume: testVolume("foo", "",
 				testLocalVolume("foo", simpleVolumeNodeAffinity("foo", "bar"))),
 		},