chore: add more test variants for prettier

Author: simschla

app/src/test/java/com/diffplug/spotless/cli/steps/PrettierJavaProcessTest.java

@@ -0,0 +1,6 @@
+package com.diffplug.spotless.cli.steps;
+
+import com.diffplug.spotless.tag.CliProcessNpmTest;
+
+@CliProcessNpmTest
+public class PrettierJavaProcessTest extends PrettierTest{}

app/src/test/java/com/diffplug/spotless/cli/steps/PrettierNativeProcessTest.java

@@ -0,0 +1,6 @@
+package com.diffplug.spotless.cli.steps;
+
+import com.diffplug.spotless.tag.CliNativeNpmTest;
+
+@CliNativeNpmTest
+public class PrettierNativeProcessTest extends PrettierTest{}