runtime: use exitStatus == 1 if main finished with exception

Also update the corresponding test.

backend.native/tests/build.gradle

@@ -1141,6 +1141,7 @@ task spread_operator_0(type: RunKonanTest) {
 task main_exception(type: RunKonanTest) {
     // TODO: cannot currently check the output because the exact stacktrace strings are unpredictable.
     // goldValue = "Uncaught exception from Kotlin's main: Throwable\n"
+    expectedExitStatus = 1
     source = "runtime/basic/main_exception.kt"
 }