Added script to run automation tests on macOS.

tests/Avalonia.IntegrationTests.Appium/macos-clean-build-test.sh

@@ -0,0 +1,8 @@
+# Cleans, builds, and runs integration tests on macOS.
+# Can be used by `git bisect run` to automatically find the commit which introduced a problem. 
+SCRIPT_DIR=$(cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd)
+cd "$SCRIPT_DIR"/../.. || exit
+git clean -xdf
+./build.sh CompileNative
+./samples/IntegrationTestApp/bundle.sh
+dotnet test tests/Avalonia.IntegrationTests.Appium/ -l "console;verbosity=detailed"