Ensure the platform is initialized to avoid NPEs

 - Soem internals of JavaFX seem to have changed, ensuing that,
at least on Mac OS, there is a NPE the first time CodeAre tries to animate it's text.
Forcing this initialization prevents that.

Author: jsotuyod

src/test/kotlin/net/sourceforge/pmd/util/fxdesigner/util/codearea/CoordinateMappingTest.kt

@@ -9,6 +9,7 @@ import io.kotest.matchers.shouldBe
 import io.kotest.assertions.throwables.shouldThrow
 import net.sourceforge.pmd.util.fxdesigner.util.codearea.PmdCoordinatesSystem.*
 import org.fxmisc.richtext.CodeArea
+import javafx.application.Platform
 
 class CoordinateMappingTest : FunSpec({
 
@@ -18,6 +19,11 @@ class CoordinateMappingTest : FunSpec({
     fun CodeArea.fromPmd(line: Int, column: Int): Int =
             getOffsetFromPmdPosition(this, line, column)
 
+    beforeSpec() {
+        // Ensure the platform is initialized to avoid NPEs
+        Platform.startup({ });
+    }
+
     test("Map normal text") {
 
         val codeArea = CodeArea("fof foo")