Address undefined behavior related to hashing enums

[j2kun]

The hashing of this untyped enum was flagged as undefined behavior in v1.4.0 by ubsan. The compiler is allowed to pick the type of the enum, and static_cast from an int to the enum (as performed by unordered_map) is UB.

[j2kun]

If you'll excuse the noise of a Google-internal stack trace, here's the ubsan error:

third_party/crosstool/v18/stable/src/libcxx/include/unordered_map:658:108: runtime error: load of value 4, which is not a valid value for type 'const TEST_CASE_TYPE'
    #0 0x7f0106474487 in operator() third_party/crosstool/v18/stable/src/libcxx/include/unordered_map:658:108
    #1 0x7f0106474487 in std::__u::pair<std::__u::__hash_iterator<std::__u::__hash_node<std::__u::__hash_value_type<TEST_CASE_TYPE, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>>, void*>*>, bool> std::__u::__hash_table<std::__u::__hash_value_type<TEST_CASE_TYPE, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>>, std::__u::__unordered_map_hasher<TEST_CASE_TYPE, std::__u::pair<TEST_CASE_TYPE const, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>>, std::__u::hash<TEST_CASE_TYPE>, std::__u::equal_to<TEST_CASE_TYPE>, true>, std::__u::__unordered_map_equal<TEST_CASE_TYPE, std::__u::pair<TEST_CASE_TYPE const, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>>, std::__u::equal_to<TEST_CASE_TYPE>, std::__u::hash<TEST_CASE_TYPE>, true>, std::__u::allocator<std::__u::pair<TEST_CASE_TYPE const, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>>>>::__emplace_unique_key_args<TEST_CASE_TYPE, std::__u::pair<TEST_CASE_TYPE const, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>> const&>(TEST_CASE_TYPE const&, std::__u::pair<TEST_CASE_TYPE const, std::__u::basic_string<char, std::__u::char_traits<char>, std::__u::allocator<char>>> const&) third_party/crosstool/v18/stable/src/libcxx/include/__hash_table:1513:21
    #2 0x7f01066effce in __emplace_unique_extract_key third_party/crosstool/v18/stable/src/libcxx/include/__hash_table:800:12
    #3 0x7f01066effce in __emplace_unique third_party/crosstool/v18/stable/src/libcxx/include/__hash_table:775:12
    #4 0x7f01066effce in insert third_party/crosstool/v18/stable/src/libcxx/include/unordered_map:1642:14
    #5 0x7f01066effce in unordered_map third_party/crosstool/v18/stable/src/libcxx/include/unordered_map:1598:3
    #6 0x7f01066effce in operator<<(std::__u::basic_ostream<char, std::__u::char_traits<char>>&, TEST_CASE_TYPE const&) third_party/openfhe/src/pke/unittest/utckksrns/UnitTestInteractiveBootstrap.cpp:71:78
    #7 0x7f01066f38da in TEST_CASE_UTCKKSRNS_INTERACTIVE_BOOT::buildTestName() const third_party/openfhe/src/pke/unittest/utckksrns/UnitTestInteractiveBootstrap.cpp:96:12
    #8 0x7f01066efcc2 in operator() third_party/openfhe/src/pke/unittest/utckksrns/UnitTestInteractiveBootstrap.cpp:112:32
    #9 0x7f01066efcc2 in gtest_UnitTestsUTCKKSRNS_INTERACTIVE_BOOT_EvalGenerateName_(testing::TestParamInfo<TEST_CASE_UTCKKSRNS_INTERACTIVE_BOOT> const&) third_party/openfhe/src/pke/unittest/utckksrns/UnitTestInteractiveBootstrap.cpp:668:1
    #10 0x7f010670a8ae in testing::internal::ParameterizedTestSuiteInfo<UTCKKSRNS_INTERACTIVE_BOOT>::RegisterTests() third_party/googletest/googletest/include/gtest/internal/gtest-param-util.h:581:15
    #11 0x7f0103b0fc69 in RegisterTests third_party/googletest/googletest/include/gtest/internal/gtest-param-util.h:736:24
    #12 0x7f0103b0fc69 in RegisterParameterizedTests third_party/googletest/googletest/src/gtest.cc:2864:34
    #13 0x7f0103b0fc69 in testing::internal::UnitTestImpl::PostFlagParsingInit() third_party/googletest/googletest/src/gtest.cc:5820:5
    #14 0x7f0103b1db32 in void testing::internal::InitGoogleTestImpl<char>(int*, char**) third_party/googletest/googletest/src/gtest.cc:6994:22
    #15 0x7f0103b12b08 in testing::InitGoogleTest(int*, char**) third_party/googletest/googletest/src/gtest.cc:7012:3
    #16 0x7f0104772ea7 in main third_party/openfhe/test/Main_TestAll.cpp:164:5
    #17 0x7f00b34c33d3 in __libc_start_main (/usr/grte/v5/lib64/libc.so.6+0x613d3) (BuildId: 9a996398ce14a94560b0c642eb4f6e94)
    #18 0x5648aceea9a9 in _start /usr/grte/v5/debug-src/src/csu/../sysdeps/x86_64/start.S:120

SUMMARY: UndefinedBehaviorSanitizer: invalid-enum-load third_party/crosstool/v18/stable/src/libcxx/include/unordered_map:658:108  (//third_party/openfhe/src/pke:pke_tests)

[yspolyakov]

@dsuponitskiy Please add an issue for this PR and also review the changes.