KVM: selftests: Add supported test cases for LoongArch

Some common KVM test cases are supported on LoongArch now as following:
  coalesced_io_test
  demand_paging_test
  dirty_log_perf_test
  dirty_log_test
  guest_print_test
  hardware_disable_test
  kvm_binary_stats_test
  kvm_create_max_vcpus
  kvm_page_table_test
  memslot_modification_stress_test
  memslot_perf_test
  set_memory_region_test

And other test cases are not supported by LoongArch such as rseq_test,
since it is not supported on LoongArch physical machine either.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>