Tests fail on iOS 11.3 and 12.0

https://travis-ci.org/apache/cordova-plugin-file/jobs/547250940
https://travis-ci.org/apache/cordova-plugin-file/jobs/547250941

Seems to be mainly problems with path comparisons, where the result is missing the containing folder, or wrong folder:

```
**************************************************
* Failures *
**************************************************
1) cordova-plugin-file-tests.tests >> File API DirectoryEntry file.spec.24 DirectoryEntry.getDirectory: create new dir with space then resolveLocalFileSystemURL
- Expected paths to match : /de create dir should be /Volumes/Sims_OSX13/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/de create dir/
2) cordova-plugin-file-tests.tests >> File API Backwards compatibility file.spec.109 should be able to resolve a file:/// URL
- Expected 'file:////Volumes/Sims_OSX13/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/file.txt' to equal 'file:///Users/chef/Library/Developer/CoreSimulator/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/file.txt'.
3) cordova-plugin-file-tests.tests >> File API resolveLocalFileSystemURL on file:// file.spec.121 should resolve native URLs returned by API
- Expected paths to match : //native.resolve.uri1 should be /Volumes/Sims_OSX13/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/native.resolve.uri1
4) cordova-plugin-file-tests.tests >> File API resolveLocalFileSystemURL on file:// file.spec.122 should resolve native URLs returned by API with localhost
- Expected paths to match : //native.resolve.uri2 should be /Volumes/Sims_OSX13/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/native.resolve.uri2
5) cordova-plugin-file-tests.tests >> File API resolveLocalFileSystemURL on file:// file.spec.123 should resolve native URLs returned by API with query string
- Expected paths to match : //native.resolve.uri3 should be /Volumes/Sims_OSX13/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/native.resolve.uri3
6) cordova-plugin-file-tests.tests >> File API resolveLocalFileSystemURL on file:// file.spec.124 should resolve native URLs returned by API with localhost and query string
- Expected paths to match : //native.resolve.uri4 should be /Volumes/Sims_OSX13/Devices/C6BFD473-7842-4EA3-A74E-5657409ED2A5/data/Containers/Data/Application/DB46067A-C7AB-46BA-A243-4475C6C1736C/Documents/native.resolve.uri4
```

Start with the Travis CI jobs linked in the issue and the six failing File API tests, especially DirectoryEntry.getDirectory and resolveLocalFileSystemURL. Compare the path and file URL expectations on iOS 11.3 and 12.0, then confirm the affected tests pass on both versions without regressions.

Written by the indexing model from the issue text.