Optimize codegen for generic SAM types

Search abstract members in unsubstituted scope to avoid computation
of substituted descriptors for each type (effectively for each SAM call)

 #KT-20055 In progress

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

@@ -203,7 +203,7 @@ public class ClosureCodegen extends MemberCodegen<KtElement> {
             erasedInterfaceFunction = getErasedInvokeFunction(funDescriptor);
         }
         else {
-            erasedInterfaceFunction = samType.getAbstractMethod().getOriginal();
+            erasedInterfaceFunction = samType.getOriginalAbstractMethod();
         }
 
         generateBridge(

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

@@ -54,8 +54,8 @@ public class SamType {
     }
 
     @NotNull
-    public SimpleFunctionDescriptor getAbstractMethod() {
-        return (SimpleFunctionDescriptor) SingleAbstractMethodUtils.getAbstractMembers(type).get(0);
+    public SimpleFunctionDescriptor getOriginalAbstractMethod() {
+        return (SimpleFunctionDescriptor) SingleAbstractMethodUtils.getAbstractMembers(getJavaClassDescriptor()).get(0);
     }
 
     @Override

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

@@ -88,7 +88,7 @@ public class SamWrapperCodegen {
                 /* isExternal = */ false
         );
         // e.g. compare(T, T)
-        SimpleFunctionDescriptor erasedInterfaceFunction = samType.getAbstractMethod().getOriginal().copy(
+        SimpleFunctionDescriptor erasedInterfaceFunction = samType.getOriginalAbstractMethod().copy(
                 classDescriptor,
                 Modality.FINAL,
                 Visibilities.PUBLIC,
@@ -167,7 +167,7 @@ public class SamWrapperCodegen {
 
         // generate sam bridges
         // TODO: erasedInterfaceFunction is actually not an interface function, but function in generated class
-        SimpleFunctionDescriptor originalInterfaceErased = samType.getAbstractMethod().getOriginal();
+        SimpleFunctionDescriptor originalInterfaceErased = samType.getOriginalAbstractMethod();
         SimpleFunctionDescriptorImpl descriptorForBridges = SimpleFunctionDescriptorImpl
                 .create(erasedInterfaceFunction.getContainingDeclaration(), erasedInterfaceFunction.getAnnotations(), originalInterfaceErased.getName(),
                         CallableMemberDescriptor.Kind.DECLARATION, erasedInterfaceFunction.getSource());

compiler/backend/src/org/jetbrains/kotlin/codegen/state/KotlinTypeMapper.java

@@ -899,7 +899,7 @@ public class KotlinTypeMapper {
                 if (expression instanceof KtLambdaExpression) {
                     SamType samType = bindingContext.get(SAM_VALUE, (KtExpression) expression);
                     if (samType != null) {
-                        return samType.getAbstractMethod().getName().asString();
+                        return samType.getOriginalAbstractMethod().getName().asString();
                     }
                 }
             }