[vm,dyn_modules] Do not share bytecode between field getter and field initializer

Profiler does not allow 2 distinct Bytecode objects to use the same
range of bytecode, as it needs to map PC to a Bytecode unambiguously.

So this change removes reuse of the field initializer bytecodes for
a field getter (in case of const fields).

TEST=pkg/vm_service/test/get_perfetto_cpu_samples_rpc_test

Change-Id: I758286f6f4fcfe2e2169bbc19ae233594e263522
Cq-Include-Trybots: luci.dart.try:vm-aot-dyn-linux-debug-x64-try,vm-aot-dyn-linux-product-x64-try,vm-dyn-linux-debug-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/436740
Commit-Queue: Alexander Markov <[email protected]>
Reviewed-by: Slava Egorov <[email protected]>

Author: alexmarkov

runtime/vm/bytecode_reader.cc

@@ -1684,16 +1684,10 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
       function.set_accessor_field(field);
       function.set_is_extension_member(is_extension_member);
       SetupFieldAccessorFunction(cls, function, type);
-      if (is_const && has_nontrivial_initializer) {
-        BytecodeLoader* loader = thread_->bytecode_loader();
-        ASSERT(loader != nullptr);
-        loader->SetOffset(function, loader->GetOffset(field));
+      if (is_static) {
+        function.AttachBytecode(Object::implicit_static_getter_bytecode());
       } else {
-        if (is_static) {
-          function.AttachBytecode(Object::implicit_static_getter_bytecode());
-        } else {
-          function.AttachBytecode(Object::implicit_getter_bytecode());
-        }
+        function.AttachBytecode(Object::implicit_getter_bytecode());
       }
       functions_->SetAt(function_index_++, function);
     }