Fix duplicate stepping filter adding on plugin start-up (KT-38628)

Review KT-CR-1301.

idea/jvm-debugger/jvm-debugger-core/src/org/jetbrains/kotlin/idea/debugger/KotlinDebuggerSettings.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.idea.debugger.stepping.KotlinSteppingConfigurableUi
 class KotlinDebuggerSettings : XDebuggerSettings<KotlinDebuggerSettings>("kotlin_debugger"), Getter<KotlinDebuggerSettings> {
     var renderDelegatedProperties: Boolean = false
     var disableKotlinInternalClasses: Boolean = true
-    var isFilterForStdlibAlreadyAdded: Boolean = false
     var debugDisableCoroutineAgent: Boolean = false
 
     companion object {

idea/jvm-debugger/jvm-debugger-core/src/org/jetbrains/kotlin/idea/debugger/filter/DebuggerFiltersUtil.kt

@@ -18,18 +18,17 @@ package org.jetbrains.kotlin.idea.debugger.filter
 
 import com.intellij.debugger.settings.DebuggerSettings
 import com.intellij.ui.classFilter.ClassFilter
-import org.jetbrains.kotlin.idea.debugger.KotlinDebuggerSettings
 
 private const val KOTLIN_STDLIB_FILTER = "kotlin.*"
 
 fun addKotlinStdlibDebugFilterIfNeeded() {
-    if (!KotlinDebuggerSettings.getInstance().isFilterForStdlibAlreadyAdded) {
-        val settings = DebuggerSettings.getInstance()!!
-        val newFilters = (settings.steppingFilters + ClassFilter(KOTLIN_STDLIB_FILTER))
+    val settings = DebuggerSettings.getInstance() ?: return
+    val existingFilters = settings.steppingFilters
 
-        settings.steppingFilters = newFilters
-
-        KotlinDebuggerSettings.getInstance().isFilterForStdlibAlreadyAdded = true
+    if (existingFilters.any { it.pattern == KOTLIN_STDLIB_FILTER }) {
+        return
     }
+
+    settings.steppingFilters = settings.steppingFilters + ClassFilter(KOTLIN_STDLIB_FILTER)
 }
 

idea/jvm-debugger/jvm-debugger-test/test/org/jetbrains/kotlin/idea/debugger/test/preference/DebuggerPreferenceKey.kt

@@ -32,7 +32,6 @@ internal object DebuggerPreferenceKeys {
 
     val DISABLE_KOTLIN_INTERNAL_CLASSES by debuggerPreferenceKey(false)
     val RENDER_DELEGATED_PROPERTIES by debuggerPreferenceKey(false)
-    val IS_FILTER_FOR_STDLIB_ALREADY_ADDED by debuggerPreferenceKey(false)
 
     val FORCE_RANKING by debuggerPreferenceKey(false)
 

idea/jvm-debugger/jvm-debugger-test/test/org/jetbrains/kotlin/idea/debugger/test/preference/SettingsMutators.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.idea.debugger.DebuggerUtils
 import org.jetbrains.kotlin.idea.debugger.KotlinDebuggerSettings
 import org.jetbrains.kotlin.idea.debugger.ToggleKotlinVariablesState
 import org.jetbrains.kotlin.idea.debugger.test.preference.DebuggerPreferenceKeys.DISABLE_KOTLIN_INTERNAL_CLASSES
-import org.jetbrains.kotlin.idea.debugger.test.preference.DebuggerPreferenceKeys.IS_FILTER_FOR_STDLIB_ALREADY_ADDED
 import org.jetbrains.kotlin.idea.debugger.test.preference.DebuggerPreferenceKeys.RENDER_DELEGATED_PROPERTIES
 import org.jetbrains.kotlin.idea.debugger.test.preference.DebuggerPreferenceKeys.SKIP_CLASSLOADERS
 import org.jetbrains.kotlin.idea.debugger.test.preference.DebuggerPreferenceKeys.SKIP_CONSTRUCTORS
@@ -29,7 +28,6 @@ internal val SettingsMutators: List<SettingsMutator<*>> = listOf(
     DebuggerSettingsMutator(SKIP_GETTERS, DebuggerSettings::SKIP_GETTERS),
     KotlinSettingsMutator(DISABLE_KOTLIN_INTERNAL_CLASSES, KotlinDebuggerSettings::disableKotlinInternalClasses),
     KotlinSettingsMutator(RENDER_DELEGATED_PROPERTIES, KotlinDebuggerSettings::renderDelegatedProperties),
-    KotlinSettingsMutator(IS_FILTER_FOR_STDLIB_ALREADY_ADDED, KotlinDebuggerSettings::isFilterForStdlibAlreadyAdded),
     KotlinVariablesModeSettingsMutator,
     JvmTargetSettingsMutator,
     ForceRankingSettingsMutator