in AppVeyor the test programs are not executable

[infrastation]

This is a follow-up to #1469.

dir run\%BUILDCONF%
 Volume in drive C has no label.
 Volume Serial Number is 1CB8-D4AA
 Directory of C:\projects\libpcap\build\run\Release
02/18/2025  03:05 PM    <DIR>          .
02/18/2025  03:05 PM    <DIR>          ..
02/18/2025  03:04 PM            99,840 activatetest.exe
02/18/2025  03:05 PM            99,328 can_set_rfmon_test.exe
02/18/2025  03:05 PM           102,912 capturetest.exe
02/18/2025  03:04 PM           120,320 filtertest.exe
02/18/2025  03:04 PM           100,864 findalldevstest-perf.exe
02/18/2025  03:04 PM           108,544 findalldevstest.exe
02/18/2025  03:04 PM           102,400 opentest.exe
02/18/2025  03:04 PM           384,512 pcap.dll
02/18/2025  03:04 PM            99,840 reactivatetest.exe
02/18/2025  03:04 PM           154,112 rpcapd.exe
02/18/2025  03:04 PM           103,424 threadsignaltest.exe
02/18/2025  03:04 PM           108,032 writecaptest.exe
              12 File(s)      1,584,128 bytes
               2 Dir(s)  52,051,533,824 bytes free

.\run\Release\filtertest.exe -h
Command exited with code -1073741515

-1073741515 stands for 0xffffffffc00001350, which stands for error code 0xc00001350, which supposedly means ".NET 3.5 is not installed" (how did it manage to link then?), which supposedly should be pre-installed (why does it fail to start then?). This is a foreign problem space for me, so Windows builds will continue not to run the tests until somebody else figures this out.

After this problem is solved, the following change should be sufficient to start running the tests:

--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -19,6 +19,7 @@ install:
   - 7z x .\npcap-sdk-1.13.zip -oc:\projects\libpcap\Win32\npcap-sdk
 
 environment:
+  BUILDCONF: Release
   #
   # The OpenSSL library on the current AppVeyor Visual Studio 2019
   # images has a weird opensslv.h that claims its 1.0.2, even though
@@ -168,4 +169,6 @@ build_script:
   - cd build
   - cmake --version
   - cmake %REMOTE% %OPENSSL_ROOT_DIR% -DPacket_ROOT=c:\projects\libpcap\Win32\%SDK% -G"%GENERATOR%" -DPacket_ROOT=c:>
-  - msbuild /m /nologo /p:Configuration=Release pcap.sln
+  - msbuild /m /nologo /p:Configuration=%BUILDCONF% pcap.sln
+  - set FILTERTEST_BIN=run\%BUILDCONF%\filtertest.exe
+  - perl ..\testprogs\TESTrun