Fix testing isolation

AS::Testing::Isolation has two ways to isolate the process:
forking and subprocessing. The second way is used on JRuby and other
platforms that don't support forking.

The way how subprocessing works is that we prepare a command to run a
new process:

```
/opt/rubies/2.3.0/bin/ruby -I{skipped_load_path} test/initializable_test.rb '' -nInitializableTests::Basic#test_Initializer_provides_context's_class_name
```

As you see, there's unescaped quote at the end of the line.
It leads to:

```
sh: -c: line 0: unexpected EOF while looking for matching `''
sh: -c: line 1: syntax error: unexpected end of file
```

This fixes tests on MRI + NO_FORK variable and on JRuby :tada:

0 files changed, 0 insertions, 0 deletions