Do not print error message to the console when we've failed to instal…

…l signal handler. (Kotlin#2118)

Otherwise, it may lead to obscure error messages in the console when users are on Windows and are not aware about signals.

kotlinx-coroutines-core/jvm/src/debug/AgentPremain.kt

@@ -69,7 +69,7 @@ internal object AgentPremain {
                 }
             }
         } catch (t: Throwable) {
-            System.err.println("Failed to install signal handler: $t")
+            // Do nothing, signal cannot be installed, e.g. because we are on Windows
         }
     }
 }