Allow running mjsunit/manual-parallel-recompile on single-core systems.

test/mjsunit/manual-parallel-recompile.js

Index: test/mjsunit/manual-parallel-recompile.js
diff --git a/test/mjsunit/manual-parallel-recompile.js b/test/mjsunit/manual-parallel-recompile.js
index f090ff497d501a136367ef21af33d040364427a9..5253487f4bb8bb9623dd0af9888b23d4afe01ef3 100644
--- a/test/mjsunit/manual-parallel-recompile.js
+++ b/test/mjsunit/manual-parallel-recompile.js
@@ -60,8 +60,10 @@ assertUnoptimized(g);
 %OptimizeFunctionOnNextCall(g, "parallel");
 f(g(2));  // Trigger optimization.
 
-assertUnoptimized(f);  // Not yet optimized.
-assertUnoptimized(g);
+if (%IsParallelRecompilationSupported()) {
+  assertUnoptimized(f);  // Not yet optimized.
+  assertUnoptimized(g);
+}
 
 %CompleteOptimization(f);  // Wait till optimized code is installed.
 %CompleteOptimization(g);