Introduce "-Xreport-output-files" to report source-output mapping for JPS

This makes "-verbose" not required for JPS to run correctly and
therefore allows to print more useful debugging stuff in the compiler
and read them in CLI, for example. The output will also be more readable
because there'll be no "output" messages

plugins/source-sections/source-sections-compiler/tests/org/jetbrains/kotlin/sourceSections/SourceSectionsTest.kt

@@ -208,7 +208,8 @@ class SourceSectionsTest : TestCaseWithTmpdir() {
                 sourceToOutput.forEach { (source, expectedOutput) ->
                     val args = arrayOf(source.canonicalPath, "-d", tmpdir.canonicalPath,
                                        "-Xplugin=${sourceSectionsPluginJar.canonicalPath}",
-                                       "-P", TEST_ALLOWED_SECTIONS.joinToString(",") { "plugin:${SourceSectionsCommandLineProcessor.PLUGIN_ID}:${SourceSectionsCommandLineProcessor.SECTIONS_OPTION.name}=$it" })
+                                       "-P", TEST_ALLOWED_SECTIONS.joinToString(",") { "plugin:${SourceSectionsCommandLineProcessor.PLUGIN_ID}:${SourceSectionsCommandLineProcessor.SECTIONS_OPTION.name}=$it" },
+                                       "-Xreport-output-files")
 
                     messageCollector.clear()
                     val outputs = arrayListOf<OutputMessageUtil.Output>()