Fail sooner and with better error message when attempting precompilation on IA32.

runtime/bin/main.cc

Index: runtime/bin/main.cc
diff --git a/runtime/bin/main.cc b/runtime/bin/main.cc
index 7e111637a5f7012443046587ffd61bdee81670b7..b1c8f90821c03e132e1ebf7761b25b1e60f0d07b 100644
--- a/runtime/bin/main.cc
+++ b/runtime/bin/main.cc
@@ -323,7 +323,7 @@ static bool ProcessGenPrecompiledSnapshotOption(
   // Ensure that we are not already running using a full snapshot.
   if (isolate_snapshot_buffer != NULL) {
     Log::PrintErr("Precompiled snapshots must be generated with"
-                  " dart_no_snapshot.");
+                  " dart_no_snapshot.\n");
     return false;
   }
   has_gen_precompiled_snapshot = true;