Print process's output line by line (MI)

For example:
was:
```
@"'\r\n` - it's \\ni=1\r\nj=2\r\nx=3\r\ny=4\r\nargc: /Users/IliaK/p/hello\r\nargc: (null)\r\n"
```

now:
```
@"'\r\n"
@"` - it's \\ni=1\r\n"
@"j=2\r\n"
@"x=3\r\n"
@"y=4\r\n"
@"argc: /Users/IliaK/p/hello\r\n"
@"argc: (null)\r\n"
```

llvm-svn: 236824