CLI: Allow running class files with '.class' extension in 'kotlin' script

Catch NoClassDefFoundError and print message with cause.

 #KT-11164 Fixed
 #KT-46171 Fixed

compiler/cli/cli-runner/src/org/jetbrains/kotlin/runner/Main.kt

@@ -144,7 +144,19 @@ object Main {
                 break
             }
             else {
-                setRunner(MainClassRunner(arg))
+                val workingDir = File(".")
+                val classFile = File(arg)
+
+                // Allow running class files with '.class' extension.
+                // In order to infer its fully qualified name, it should be located in the current working directory or a subdirectory of it
+                val className =
+                    if (arg.endsWith(".class") && classFile.exists() && classFile.canonicalPath.contains(workingDir.canonicalPath)) {
+                        classFile.canonicalFile.toRelativeString(workingDir.canonicalFile)
+                            .removeSuffix(".class")
+                            .replace(File.separatorChar, '.')
+                    } else arg
+
+                setRunner(MainClassRunner(className))
                 restAsArguments()
                 break
             }

compiler/cli/cli-runner/src/org/jetbrains/kotlin/runner/runners.kt

@@ -25,7 +25,7 @@ import java.net.URLClassLoader
 import java.util.jar.Attributes
 import java.util.jar.JarFile
 
-class RunnerException(message: String) : RuntimeException(message)
+class RunnerException(message: String, cause: Throwable? = null) : RuntimeException(message, cause)
 
 abstract class AbstractRunner : Runner {
     protected abstract val className: String
@@ -40,6 +40,12 @@ abstract class AbstractRunner : Runner {
         }
         catch (e: ClassNotFoundException) {
             throw RunnerException("could not find or load main class $className")
+        } catch (e: NoClassDefFoundError) {
+            val message = """
+                could not find or load main class $className
+                Caused by: $e
+            """.trimIndent()
+            throw RunnerException(message)
         }
 
         val main = try {