[CLI] Introduce new compiler arguments for registering compiler plugins

With new syntax each plugin should be registered in separate argument with syntax
`-Xcompiler-plugin=classpath1,classpath2[=argument1=value1,argument2=value2]`

compiler/test-infrastructure-utils/tests/org/jetbrains/kotlin/script/scriptTestUtil.kt

@@ -20,5 +20,5 @@ fun loadScriptingPlugin(configuration: CompilerConfiguration) {
             KOTLIN_SCRIPTING_JVM_JAR
         ).map { File(libPath, it).path }
     }
-    PluginCliParser.loadPluginsSafe(pluginClasspath, null, configuration)
-}
+    PluginCliParser.loadPluginsSafe(pluginClasspath, emptyList(), emptyList(), configuration)
+}