Do not queue bg task under read action

Relates to #EA-218701

idea/idea-jvm/src/org/jetbrains/kotlin/idea/scratch/compile/KtScratchExecutionSession.kt

@@ -16,7 +16,6 @@ import com.intellij.openapi.project.DumbService
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.Computable
 import com.intellij.openapi.util.io.FileUtil
-import com.intellij.util.concurrency.NonUrgentExecutor
 import org.jetbrains.kotlin.codegen.ClassBuilderFactories
 import org.jetbrains.kotlin.codegen.KotlinCodegenFacade
 import org.jetbrains.kotlin.codegen.filterClassFiles
@@ -56,9 +55,8 @@ class KtScratchExecutionSession(
         if (!executor.checkForErrors(psiFile, expressions)) return
 
         val project = file.project
-        ReadAction.nonBlocking {
+        when (val result = runReadAction { KtScratchSourceFileProcessor().process(expressions) }) {
-                when (val result = KtScratchSourceFileProcessor().process(expressions)) {
+            is KtScratchSourceFileProcessor.Result.Error -> return executor.errorOccurs(result.message, isFatal = true)
-                    is KtScratchSourceFileProcessor.Result.Error -> return@nonBlocking executor.errorOccurs(result.message, isFatal = true)
             is KtScratchSourceFileProcessor.Result.OK -> {
                 LOG.printDebugMessage("After processing by KtScratchSourceFileProcessor:\n ${result.code}")
 
@@ -66,6 +64,7 @@ class KtScratchExecutionSession(
                     override fun run(indicator: ProgressIndicator) {
                         backgroundProcessIndicator = indicator
 
+                        ReadAction.nonBlocking {
                             val modifiedScratchSourceFile = runReadAction {
                                 KtPsiFactory(psiFile.project).createFileWithLightClassSupport("tmp.kt", result.code, psiFile)
                             }
@@ -83,14 +82,16 @@ class KtScratchExecutionSession(
                                 )
                             }
                         }
+                            .inSmartMode(project)
+                            .wrapProgress(indicator)
+                            .withDocumentsCommitted(project)
+                            .executeSynchronously()
+                    }
                 }.queue()
             }
         }
-            }
+
-            .inSmartMode(project)
+
-            .expireWith(project)
-            .withDocumentsCommitted(project)
-            .submit(NonUrgentExecutor.getInstance())
     }
 
     private fun runCommandLine(