disk_interface: Restore toleration of missing files in RemoveFile on …

…Windows

Revise the logic from commit 2d7f7e5 (Delete read-only files on
Windows, too, 2020-12-07) to check if `GetFileAttributes` or
`DeleteFile` failed due either variant of the file/path-not-found error.

Issue: ninja-build#1886

src/disk_interface.cc

@@ -268,16 +268,23 @@ int RealDiskInterface::RemoveFile(const string& path) {
 #ifdef _WIN32
   DWORD attributes = GetFileAttributes(path.c_str());
   if (attributes == INVALID_FILE_ATTRIBUTES) {
-    if (GetLastError() == ERROR_FILE_NOT_FOUND) {
+    DWORD win_err = GetLastError();
+    if (win_err == ERROR_FILE_NOT_FOUND || win_err == ERROR_PATH_NOT_FOUND) {
       return 1;
     }
   } else if (attributes & FILE_ATTRIBUTE_READONLY) {
     // On non-Windows systems, remove() will happily delete read-only files.
     // On Windows Ninja should behave the same:
     //   https://github.com/ninja-build/ninja/issues/1886
+    // Skip error checking.  If this fails, accept whatever happens below.
     SetFileAttributes(path.c_str(), attributes & ~FILE_ATTRIBUTE_READONLY);
   }
   if (!DeleteFile(path.c_str())) {
+    DWORD win_err = GetLastError();
+    if (win_err == ERROR_FILE_NOT_FOUND || win_err == ERROR_PATH_NOT_FOUND) {
+      return 1;
+    }
+    // Report as remove(), not DeleteFile(), for cross-platform consistency.
     Error("remove(%s): %s", path.c_str(), GetLastErrorString().c_str());
     return -1;
   }