fix context management

Author: SBOne-Kenobi

utbot-junit-contest/src/main/kotlin/org/utbot/contest/ContestEstimator.kt

@@ -139,7 +139,7 @@ enum class Tool {
             classFqn: String
         ) {
             val classStats: StatsForClass = try {
-                withUtContext(UtContext(project.classloader)) {
+                withUtContext(ContextManager.createNewContext(project.classloader)) {
                     runGeneration(
                         project.name,
                         cut,

utbot-junit-contest/src/main/kotlin/org/utbot/contest/ContextManager.kt

@@ -0,0 +1,23 @@
+package org.utbot.contest
+
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.cancelChildren
+import org.utbot.framework.plugin.api.util.UtContext
+
+object ContextManager {
+    private val currentContexts = mutableListOf<UtContext>()
+
+    fun createNewContext(classLoader: ClassLoader) =
+        UtContext(classLoader).apply {
+            currentContexts.add(this)
+        }
+
+    fun cancelAll() {
+        currentContexts.forEach {
+            it.cancelChildren()
+            it.cancel()
+        }
+        currentContexts.clear()
+    }
+
+}

utbot-junit-contest/src/main/kotlin/org/utbot/monitoring/StatisticsMonitoring.kt

@@ -14,6 +14,7 @@ import org.utbot.common.ThreadBasedExecutor
 import org.utbot.common.bracket
 import org.utbot.common.info
 import org.utbot.contest.ContestEstimatorJdkInfoProvider
+import org.utbot.contest.ContextManager
 import org.utbot.contest.GlobalStats
 import org.utbot.contest.Paths
 import org.utbot.contest.Tool
@@ -76,8 +77,7 @@ fun main(args: Array<String>) {
 
         }
 
-        utContext.cancelChildren()
-        utContext.cancel()
+        ContextManager.cancelAll()
         ConcreteExecutor.defaultPool.forceTerminateProcesses()
         System.gc()
     }