[JS IR BE] Properly handle primary constructors

- force primary constructor to be created by codegen
 - make sure initializer is invoked once in primary constructor
 - make one of coroutine constructor primary
 - remove hack from codegen

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/AbstractSuspendFunctionsLowering.kt

@@ -392,7 +392,7 @@ abstract class AbstractSuspendFunctionsLowering<C : CommonBackendContext>(val co
                 coroutineClass.defaultType,
                 isInline = false,
                 isExternal = false,
-                isPrimary = false
+                isPrimary = true
             ).apply {
                 d.bind(this)
                 parent = coroutineClass