Debug/x64 flavor of several samples actually builds x86

[austinkinross]

Repro steps:

1. Clone repo
2. Open 'SqueezeNetObjectDetection.sln' (after performing the 'WINDOWS_WINMD' workaround here)
3. Select the Debug/x64 build config and build the solution

Expected result: it builds a Debug/x64 version of SqueezeNetObjectDetectionCPP.exe
Actual result: it builds a Debug/x86 version of SqueezeNetObjectDetectionCPP.exe

Build log:

1>pch.cpp
1>main.cpp
1>SqueezeNetObjectDetectionCPP.vcxproj -> ...\Samples\SqueezeNetObjectDetection\Desktop\cpp\Debug\SqueezeNetObjectDetectionCPP.exe
========== Build: 1 succeeded, 0 failed, 3 up-to-date, 0 skipped ==========

Dumpbin:

Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file \SqueezeNetObjectDetection\Desktop\cpp\Debug\SqueezeNetObjectDetectionCPP.exe

PE signature found

File Type: EXECUTABLE IMAGE

FILE HEADER VALUES
             14C machine (x86)
               A number of sections
        5CED9484 time date stamp Tue May 28 13:05:24 2019
               0 file pointer to symbol table
               0 number of symbols
              E0 size of optional header
             102 characteristics
                   Executable
                   32 bit word machine

Changing the following lines of SqueezeNetObjectDetection.sln:

{2BF804D4-DAA2-42BE-9F21-0E94F021EF53}.Debug|x64.ActiveCfg = Debug|Win32
{2BF804D4-DAA2-42BE-9F21-0E94F021EF53}.Debug|x64.Build.0 = Debug|Win32

to this fixes the problem:

{2BF804D4-DAA2-42BE-9F21-0E94F021EF53}.Debug|x64.ActiveCfg = Debug|x64
{2BF804D4-DAA2-42BE-9F21-0E94F021EF53}.Debug|x64.Build.0 = Debug|x64

By inspection, it looks like other projects have the same issue too.