Allow regexp functions to be optimized in background

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index 5d5be9a44306b5900749c8b5337106e77c1c8013..dd2ddee1a860163ce34f7c1145e19e7e3097db19 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -1288,11 +1288,8 @@ RawError* Compiler::CompileOptimizedFunction(Thread* thread,
 
   // Optimization must happen in non-mutator/Dart thread if background
   // compilation is on. OSR compilation still occurs in the main thread.
-  // TODO(Srdjan): Remove assert allowance for regular expression functions
-  // once they can be compiled in background.
   ASSERT((osr_id != kNoOSRDeoptId) || !FLAG_background_compilation ||
-         !thread->IsMutatorThread() ||
-         function.IsIrregexpFunction());
+         !thread->IsMutatorThread());
   CompilationPipeline* pipeline =
       CompilationPipeline::New(thread->zone(), function);
   return CompileFunctionHelper(pipeline,