DbgEng adapter should hide the window of dbgsrv.exe

[xusheng6]

Right now when we use the DbgEng adapter, a Window pops up for the dbgsrv.exe. We should set the appropriate parameters for CreateProcessA to make it hide the window: https://github.com/Vector35/debugger/blob/a125a23937f2295a0d37f1d90b2faa6299e003df/core/adapters/dbgengadapter.cpp#L214