VM: Avoid allocating strings when disassembling code.

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index 25fad986f195719a9875322bf279c3cd151dbf7f..3972b3300fb0c256f9441fb07169b424d855b186 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -1341,14 +1341,10 @@ static RawError* CompileFunctionHelper(CompilationPipeline* pipeline,
     }
 
     if (FLAG_disassemble && FlowGraphPrinter::ShouldPrint(function)) {
-      SafepointOperationScope safepoint_scope(thread);
-      NoHeapGrowthControlScope no_growth_control;
       Disassembler::DisassembleCode(function, optimized);
     } else if (FLAG_disassemble_optimized &&
                optimized &&
                FlowGraphPrinter::ShouldPrint(function)) {
-      SafepointOperationScope safepoint_scope(thread);
-      NoHeapGrowthControlScope no_growth_control;
       Disassembler::DisassembleCode(function, true);
     }