[pgAdmin4][Patch] RM #3277 Runtime startup error handling is brokenon Windows

Attached is the patch file to fix RM #3277 Runtime startup error handling is broken on Windows. I have figure out the crash at the following call of Server.cpp(line no 326):

When application exits due to some error it throws BEX refers to Buffer Overflow Exception, when I debug and found that it throws BEX for above function call. I have replace that call with the following:

PyRun_SimpleFile(cp, m_appfile_utf8.data())

Anyways we have open the file using fopen() at the top of the function then why to open that again using fdopen() in the first call. 

Tested the patch with Python 3.5 and 3.6, please review it.
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