message: Making GCC happy
  Summary:
  In the OSS build, gcc admitted:
  ```
  sorry, unimplemented: non-trivial designated initializers not supported
  ```
  So let's not do that.
diff: @@ -248,7 +248,8 @@ bool operator==(const CandidateSequence& a, const CandidateSequence& b) {
  }
  static CandidateInstructionCore to_core(IRInstruction* insn) {
  - CandidateInstructionCore core{.opcode = insn->opcode()};
  + CandidateInstructionCore core;
  + core.opcode = insn->opcode();
  if (insn->has_method()) {
  core.method = insn->get_method();
  } else if (insn->has_field()) {
  @@ -1069,7 +1070,9 @@ static CandidateSequence normalize(DexMethod* method,
  std::unordered_map<reg_t, reg_t> map;
  reg_t next_arg{pcs.temp_regs};
  reg_t next_temp{0};
  - CandidateSequence cs{.size = pcs.size, .temp_regs = pcs.temp_regs};
  + CandidateSequence cs;
  + cs.size = pcs.size;
  + cs.temp_regs = pcs.temp_regs;
  std::vector<reg_t> arg_regs;
  auto normalize_use = [&map, &next_arg, &arg_regs](reg_t reg, bool wide) {
  auto it = map.find(reg);
  @@ -1089,7 +1092,8 @@ static CandidateSequence normalize(DexMethod* method,
  return mapped_reg;
  };
  for (auto insn : pcs.insns) {
  - CandidateInstruction ci{.core = to_core(insn)};
  + CandidateInstruction ci;
  + ci.core = to_core(insn);
  for (size_t i = 0; i < insn->srcs_size(); i++) {
  ci.srcs.push_back(normalize_use(insn->src(i), insn->src_is_wide(i)));
  }
  