Avoid self-suppression

mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/addSuppressed.kt

@@ -7,6 +7,9 @@ private var isAddSuppressedSupported: Boolean = true
 @MiraiInternalAPI
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER")
 actual fun Throwable.addSuppressed(e: Throwable) {
+    if (this === e) {
+        return
+    }
     if (!isAddSuppressedSupported) {
         return
     }

mirai-core/src/jvmMain/kotlin/net/mamoe/mirai/utils/addSuppressed.kt

@@ -5,6 +5,9 @@ private var isAddSuppressedSupported: Boolean = true
 @MiraiInternalAPI
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER")
 actual fun Throwable.addSuppressed(e: Throwable) {
+    if (this === e) {
+        return
+    }
     if (!isAddSuppressedSupported) {
         return
     }