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.go

@@ -1383,9 +1383,6 @@ func validateLocalVolumeSource(ls *core.LocalVolumeSource, fldPath *field.Path)
 		return allErrs
 	}
 
-	if !path.IsAbs(ls.Path) {
-		allErrs = append(allErrs, field.Invalid(fldPath, ls.Path, "must be an absolute path"))
-	}
 	allErrs = append(allErrs, validatePathNoBacksteps(ls.Path, fldPath.Child("path"))...)
 	return allErrs
 }