Remove the debugger_ field from Isolate in a PRODUCT build

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index bc465b30bf484e1163d644dc051f57c2286723f2..5e842601e5ca82716a2884d67e3aa5df16d74d19 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -232,6 +232,7 @@ DEFINE_RUNTIME_ENTRY(CompileFunction, 1) {
 }
 
 bool Compiler::CanOptimizeFunction(Thread* thread, const Function& function) {
+#if !defined(PRODUCT)
   if (FLAG_support_debugger) {
     Isolate* isolate = thread->isolate();
     if (isolate->debugger()->IsStepping() ||
@@ -242,6 +243,7 @@ bool Compiler::CanOptimizeFunction(Thread* thread, const Function& function) {
       return false;
     }
   }
+#endif
   if (function.deoptimization_counter() >=
       FLAG_max_deoptimization_counter_threshold) {
     if (FLAG_trace_failed_optimization_attempts ||
@@ -1350,9 +1352,11 @@ static RawObject* CompileFunctionHelper(CompilationPipeline* pipeline,
                 per_compile_timer.TotalElapsedTime());
     }
 
+#if !defined(PRODUCT)
     if (FLAG_support_debugger) {
       isolate->debugger()->NotifyCompilation(function);
     }
+#endif
 
     if (FLAG_disassemble && FlowGraphPrinter::ShouldPrint(function)) {
       Disassembler::DisassembleCode(function, result, optimized);