Increase heap size for gradle importing tests due to memory

leak in the gradle daemon
#KT-32731 Fixed

idea/idea-gradle/tests/org/jetbrains/kotlin/idea/codeInsight/gradle/GradleImportingTestCase.kt

@@ -93,6 +93,17 @@ abstract class GradleImportingTestCase : ExternalSystemImportingTestCase() {
 
     open fun isApplicableTest(): Boolean = true
 
+    open fun jvmHeapArgsByGradleVersion(version: String) : String = when {
+        version.startsWith("4.") ->
+            // work-around due to memory leak in class loaders in gradle. The amount of used memory in the gradle daemon
+            // is drammatically increased on every reimport of project due to sequential compilation of build scripts.
+            // see more details in https://github.com/gradle/gradle/commit/b483d29f315758913791fe58d572fa6bafa0395c
+            "-Xmx256m -XX:MaxPermSize=64m"
+        else ->
+            // 128M should be enough for gradle 5.0+ (leak is fixed), and <4.0 (amount of tests is less)
+            "-Xmx128m -XX:MaxPermSize=64m"
+    }
+
     override fun setUp() {
         myJdkHome = IdeaTestUtil.requireRealJdkHome()
         super.setUp()
@@ -114,7 +125,7 @@ abstract class GradleImportingTestCase : ExternalSystemImportingTestCase() {
         }
 
         GradleSettings.getInstance(myProject).gradleVmOptions =
-            "-Xmx128m -XX:MaxPermSize=64m -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=${System.getProperty("user.dir")}"
+            "${jvmHeapArgsByGradleVersion(gradleVersion)} -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=${System.getProperty("user.dir")}"
 
         System.setProperty(ExternalSystemExecutionSettings.REMOTE_PROCESS_IDLE_TTL_IN_MS_KEY, GRADLE_DAEMON_TTL_MS.toString())
         configureWrapper()