JVM Cli: Proper Main-class manifest attribute for JvmStatic entry point.

`findMainClass` could handle main entry point from object and companion
object, not just top-level function.

Fixes [KT-32376](https://youtrack.jetbrains.com/issue/KT-32376).

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/findMainClass.kt

@@ -9,17 +9,35 @@ import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.fileClasses.JvmFileClassUtil
 import org.jetbrains.kotlin.idea.MainFunctionDetector
 import org.jetbrains.kotlin.name.FqName
-import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.resolve.BindingContext
 
 fun findMainClass(bindingContext: BindingContext, languageVersionSettings: LanguageVersionSettings, files: List<KtFile>): FqName? {
     val mainFunctionDetector = MainFunctionDetector(bindingContext, languageVersionSettings)
     return files.asSequence()
         .map { file ->
-            if (mainFunctionDetector.hasMain(file.declarations))
-                JvmFileClassUtil.getFileClassInfoNoResolve(file).facadeClassFqName
-            else
-                null
+            mainFunctionDetector.findMainFunction(file)?.let { mainFunction ->
+                if (mainFunction.isTopLevel) {
+                    JvmFileClassUtil.getFileClassInfoNoResolve(file).facadeClassFqName
+                } else {
+                    val parent = mainFunction.getParentOfType<KtClassOrObject>(strict = true)
+                    if (parent is KtObjectDeclaration && parent.isCompanion()) {
+                        mainFunction.fqName?.parent()?.parent()
+                    } else {
+                        mainFunction.fqName?.parent()
+                    }
+                }
+            }
         }
         .singleOrNull { it != null }
 }
+
+private fun MainFunctionDetector.findMainFunction(container: KtDeclarationContainer): KtNamedFunction? =
+    container.declarations.mapNotNull { declaration ->
+        when (declaration) {
+            is KtNamedFunction -> declaration.takeIf(::isMain)
+            is KtDeclarationContainer -> findMainFunction(declaration)
+            else -> null
+        }
+    }.singleOrNull()