Fix "testUnresolvedDependency"

This fix is work-around fixing incompatibility issue between gradle
tooling api bundled in IDEA and gradle tooling api in gradle 4.x.
When null messages were logged it resulted in the following error:
"java.io.StreamCorruptedException: invalid stream header: ED000573"

idea/kotlin-gradle-tooling/src/KotlinMPPGradleModelBuilder.kt

@@ -273,7 +273,7 @@ class KotlinMPPGradleModelBuilder : ModelBuilderService {
     private fun safelyGetArguments(compileKotlinTask: Task, accessor: Method?) = try {
         accessor?.invoke(compileKotlinTask) as? List<String>
     } catch (e: Exception) {
-        logger.info(e.message, e)
+        logger.info(e.message ?: "Unexpected exception: $e", e)
         null
     } ?: emptyList()
 

idea/kotlin-gradle-tooling/src/KotlinMPPGradleModelBuilder.kt.181

@@ -264,7 +264,7 @@ class KotlinMPPGradleModelBuilder : ModelBuilderService {
     private fun safelyGetArguments(compileKotlinTask: Task, accessor: Method?) = try {
         accessor?.invoke(compileKotlinTask) as? List<String>
     } catch (e: Exception) {
-        logger.info(e.message, e)
+        logger.info(e.message ?: "Unexpected exception: $e", e)
         null
     } ?: emptyList()