Handle NPE

Author: exoego

scalac-scoverage-plugin/src/main/scala/scoverage/plugin.scala

@@ -108,7 +108,11 @@ class ScoverageInstrumentationComponent(val global: Global, extraAfterPhase: Opt
   private var coverageFilter: CoverageFilter = AllCoverageFilter
 
   private val isScalaJsEnabled: Boolean = {
-    rootMirror.getClassIfDefined("scala.scalajs.js.Any") != NoSymbol
+    try {
+      rootMirror.getClassIfDefined("scala.scalajs.js.Any") != NoSymbol
+    } catch {
+      case _: Throwable => false
+    }
   }
 
   def setOptions(options: ScoverageOptions): Unit = {