Enable SMT2 solver tests on Windows

There is no reason the solver shouldn't be tested on Windows.

Author: tautschnig

buildspec-windows.yml

@@ -40,6 +40,10 @@ phases:
         $env:Path = "C:\tools\cygwin\bin;$env:Path"
         cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -C regression test BUILD_ENV=MSVC" '
 
+      - |
+        $env:Path = "$pwd\src\solvers;C:\tools\cygwin\bin;$env:Path"
+        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -C regression/cbmc test-cprover-smt2 BUILD_ENV=MSVC" '
+
       - |
         $env:Path = "C:\tools\cygwin\bin;$env:Path"
         cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -C regression/cbmc test-paths-lifo BUILD_ENV=MSVC" '