Optimize getSingleAbstractMethodOrNull

Searching for the single abstract method leads to computing
whole member scopes of given intrefaces, especially when
they contain a lot of methods (i.e. they're definitely not SAMs)

On the other side this method is very hot because it's called
for each Java interface used as a type for some value parameter
(for building SAM adapters)

The idea is to apply some heuristics to understand using only
JavaMethod and supertypes that this interface is definitely not a SAM

idea/idea-analysis/src/org/jetbrains/kotlin/idea/search/usagesSearch/ExpressionsOfTypeProcessor.kt

@@ -52,6 +52,7 @@ import org.jetbrains.kotlin.idea.util.FuzzyType
 import org.jetbrains.kotlin.idea.util.ProjectRootsUtil
 import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocName
+import org.jetbrains.kotlin.load.java.descriptors.JavaClassDescriptor
 import org.jetbrains.kotlin.load.java.sam.SingleAbstractMethodUtils
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
@@ -508,7 +509,7 @@ class ExpressionsOfTypeProcessor(
                                 testLog?.add("Resolved java class to descriptor: ${psiClass.qualifiedName}")
 
                                 val resolutionFacade = KotlinCacheService.getInstance(project).getResolutionFacadeByFile(psiClass.containingFile, JvmPlatform)
-                                val classDescriptor = psiClass.resolveToDescriptor(resolutionFacade)
+                                val classDescriptor = psiClass.resolveToDescriptor(resolutionFacade) as? JavaClassDescriptor
                                 if (classDescriptor != null && SingleAbstractMethodUtils.getSingleAbstractMethodOrNull(classDescriptor) != null) {
                                     addSamInterfaceToProcess(psiClass)
                                 }