[BugFix] Defaulting passing_devices to None

[vmoens]

Description

• The default value of the parameter "passing_device" of the constructor of SyncDataCollect has been changed to None.
• The code of the constructor of SyncDataCollect has been changed so that if the user does not provide default value of "passing_device", it will have the same device value as the "device" parameter or the device specified inside the "policy" parameter.
• The default value of the parameter "passing_devices" of the constructor of _MultiDataCollector has been changed to None.
• The code of the constructor of _MultiDataCollector has been changed so that if the user does not provide default value of "passing_devices", it will have the same device values as the "devices" parameter or the devices specified inside the "policy" parameter.

Motivation and Context

It fixes the open issue #433

Currently, if the user does not specify the "passing_device" or "passing_devices" parameter, the collector class assumes the output data will be stored in the CPU RAM by default. However, this may cause confusion because in the case that the user specifies the model to be run in the GPU via the "policy", "device" or "devices" parameter, he may not aware that the output data will actually be stored in the CPU RAM instead of the GPU RAM. I solve this possible confusion by changing the default RAM location of the output data to be same as the "policy", "device" or "devices" parameter's RAM location, if the user does NOT specify the "passing_device" or "passing_devices" parameter. However, the output RAM location will follow the "passing_device" or "passing_devices" parameter if the user DOES specify.

• I have raised an issue to propose this change (required for new features and bug fixes)

Types of changes

What types of changes does your code introduce? Remove all that do not apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds core functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)
• Example (update in the folder of examples)

Checklist

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• I have read the CONTRIBUTION guide (required)
• My change requires a change to the documentation.
• I have updated the tests accordingly (required for a bug fix or a new feature).
• I have updated the documentation accordingly.