Write kotlin metadata on class-files for coroutine state machines

Otherwise it breaks JPS assumptions, that leads to exceptions like:
Error:Kotlin: [Internal Error] java.lang.AssertionError: Couldn't load KotlinClass from /Users/jetbrains/IdeaProjects/KotlinPlaygroundBeta11/out/production/KotlinPlaygroundBeta11/Counter$both$1.class; it may happen because class doesn't have valid Kotlin annotations
    at org.jetbrains.kotlin.build.GeneratedJvmClass.<init>(generatedFiles.kt:36)
    at org.jetbrains.kotlin.jps.build.KotlinBuilder.getGeneratedFiles(KotlinBuilder.kt:469)
    at org.jetbrains.kotlin.jps.build.KotlinBuilder.doBuild(KotlinBuilder.kt:241)
    at org.jetbrains.kotlin.jps.build.KotlinBuilder.build(KotlinBuilder.kt:140)
...

compiler/backend/src/org/jetbrains/kotlin/codegen/ClosureCodegen.java

@@ -233,10 +233,7 @@ public class ClosureCodegen extends MemberCodegen<KtElement> {
     protected void generateKotlinMetadataAnnotation() {
         FunctionDescriptor freeLambdaDescriptor = createFreeLambdaDescriptor(funDescriptor);
         Method method = v.getSerializationBindings().get(METHOD_FOR_FUNCTION, funDescriptor);
-
-        // Can be null for named suspend function
-        if (method == null) return;
-
+        assert method != null : "No method for " + funDescriptor;
         v.getSerializationBindings().put(METHOD_FOR_FUNCTION, freeLambdaDescriptor, method);
 
         final DescriptorSerializer serializer =

compiler/backend/src/org/jetbrains/kotlin/codegen/coroutines/CoroutineCodegen.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.descriptors.impl.SimpleFunctionDescriptorImpl
 import org.jetbrains.kotlin.descriptors.impl.ValueParameterDescriptorImpl
+import org.jetbrains.kotlin.load.kotlin.header.KotlinClassHeader
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtDeclarationWithBody
 import org.jetbrains.kotlin.psi.KtElement
@@ -43,6 +44,7 @@ import org.jetbrains.kotlin.types.typeUtil.asTypeProjection
 import org.jetbrains.kotlin.types.typeUtil.makeNullable
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import org.jetbrains.kotlin.utils.singletonOrEmptyList
+import org.jetbrains.org.objectweb.asm.AnnotationVisitor
 import org.jetbrains.org.objectweb.asm.MethodVisitor
 import org.jetbrains.org.objectweb.asm.Opcodes
 import org.jetbrains.org.objectweb.asm.Type
@@ -301,6 +303,17 @@ class CoroutineCodegen(
         )
     }
 
+    override fun generateKotlinMetadataAnnotation() {
+        if (originalSuspendLambdaDescriptor != null) {
+            super.generateKotlinMetadataAnnotation()
+        }
+        else {
+            writeKotlinMetadata(v, state, KotlinClassHeader.Kind.SYNTHETIC_CLASS, 0) {
+                // Do not write method metadata for raw coroutine state machines
+            }
+        }
+    }
+
     companion object {
 
         @JvmStatic