[lldb] Fix API test for file redirection to existing files (#114119)
API test failed for remote platform in
[#112657](https://github.com/llvm/llvm-project/pull/112657)
Previously when putting files onto remote platform, I used `platform
file write -d <data>` which actually required a `platform file open
<path>` first in order to obtain a file descriptor.
eg. in file
[TestGDBRemotePlatformFile.py](https://github.com/llvm/llvm-project/blob/94e7d9c0bfe517507ea08b00fb00c32fb2837a82/lldb/test/API/functionalities/gdb_remote_client/TestGDBRemotePlatformFile.py#L24-L32)
To fix this, use the `platform put-file` method, which is used in the
`redirect_stdin` from this test already.