8262097: Improve CompilerConfig ergonomics to fix a VM crash after JDK-8261229

Reviewed-by: iveresov, kvn

Author: DamonFool

src/hotspot/share/compiler/compilerDefinitions.cpp

@@ -555,6 +555,8 @@ void CompilerConfig::ergo_initialize() {
  if (NeverActAsServerClassMachine) {
  set_client_emulation_mode_flags();
  }
+ } else if (!has_c2() && !is_jvmci_compiler()) {
+ set_client_emulation_mode_flags();
  }
 
  set_legacy_emulation_flags();