Summary:
There are 4 signals used for various output from the debugger:
- applicationOutput: emitted when got stream record from the 'target' channel
- userCommandOutput: emitted when got stream record from the 'console' channel and it's a user command
- internalCommandOutput: emitted when got stream record from the 'console' channel and it's not a user command
- internalOutput: emitted when got stream record from the 'log' channel or stderr from the debugger

And there are 2 output toolviews when debugging.
- The normal Debug Output panel controled by MIDebugJob
    * Shows applicationOutput, via MIDebugSession::inferiorOutputLines
    * Shows internalCommandOutput, via MIDebugSession::debuggerInternalCommandOutput
- The GDBOutputWidget which is part of the GDB plugin
    * Shows userCommandOutput, via MIDebugSession::debuggerUserCommandOutput
    * Shows internalCommandOutput, via MIDebugSession::debuggerInternalCommandOutput
    * Shows internalOutput, via MIDebugSession::debuggerInternalOutput

This should match the old behavior for toolviews and fixes the testStdOut unit test.

Test Plan: gdb unit tests

Reviewers: #kdevelop, apol

Reviewed By: #kdevelop, apol

Subscribers: kdevelop-devel

Differential Revision: https://phabricator.kde.org/D2175