Add support for using array of scalar as key field in Cpp (#7623)

* add support for using array of scalar as key field

* update cmakelist and test.cpp to include the tests

* update bazel rule

* address comments

* clang format

* delete comment

* delete comment

* address the rest of the commnets

* address comments

* update naming in test file

* format build file

* buildifier

* make keycomparelessthan call keycomparewithvalue

* update to use flatbuffer array instead of raw pointer

* clang

* format

* revert format

* revert format

* update

* run generate_code.py

* run code generator

* revert changes by generate_code.py

* fist run make flatc and then run generate_code.py

Co-authored-by: Wen Sun <sunwen@google.com>

tests/BUILD.bazel

@@ -22,6 +22,9 @@ cc_test(
         "is_quiet_nan.h",
         "json_test.cpp",
         "json_test.h",
+        "key_field/key_field_sample_generated.h",
+        "key_field_test.cpp",
+        "key_field_test.h",
         "monster_test.cpp",
         "monster_test.h",
         "monster_test_bfbs_generated.h",
@@ -63,6 +66,7 @@ cc_test(
         ":evolution_test/evolution_v2.json",
         ":include_test/include_test1.fbs",
         ":include_test/sub/include_test2.fbs",
+        ":key_field/key_field_sample.fbs",
         ":monster_extra.fbs",
         ":monster_test.bfbs",
         ":monster_test.fbs",