Update CI scripts.

ci/scripts/build.windows.script.ps1

@@ -12,7 +12,9 @@ cmd.exe /c "`"${VS_INSTALL_DIR}\VC\Auxiliary\Build\vcvarsall.bat`" $EIGEN_CI_MSV
 
 # Create and enter build directory.
 $rootdir = Get-Location
-mkdir $EIGEN_CI_BUILDDIR
+if (-Not (Test-Path ${EIGEN_CI_BUILDDIR})) {
+    mkdir $EIGEN_CI_BUILDDIR
+}
 cd $EIGEN_CI_BUILDDIR
 
 # We need to split EIGEN_CI_ADDITIONAL_ARGS, otherwise they are interpretted

ci/scripts/common.windows.before_script.ps1

@@ -1,7 +1,8 @@
 echo "Running ${CI_JOB_NAME}"
 
 # Print configuration variables.
-Get-Variable | findstr EIGEN
+Get-Variable EIGEN* | Format-Table -Wrap
+Get-Variable CMAKE* | Format-Table -Wrap
 
 # Run a custom before-script command.
 if ("${EIGEN_CI_BEFORE_SCRIPT}") { Invoke-Expression -Command "${EIGEN_CI_BEFORE_SCRIPT}" }