[C++] remove static_cast expression (#5440)

* [C++] remove static_cast expression

* [C++] Add unit test for native_type usage

* [C++] Add flatc compilation for native_type_test.fbs

* [C++] update CMakeLists to compile native_type_test.fbs properly

* Update BUILD file for bazel

* [C++] Add generated native_type_test_generated.h and fix arguments for flatc according to CMakeList

* [C++] remove "= default" from constructor to support old compilers

* Update BUILD file for bazel, attempt 2

* [C++] Workaround for MSVC 2010 for the issue with std::vector and explicitly aligned custom data types

* Update BUILD file for bazel, attempt 3

* Update BUILD file for bazel, attempt 4

* Update BUILD file for bazel, attempt 5

* Update BUILD file for bazel, attempt 6

* [C++] Workaround for MSVC 2010 for the issue with std::vector and explicitly aligned custom data types Part 2

* [C++] Keep only one optional parameter to compile_flatbuffers_schema_to_cpp_opt

* native_type_test.fbs style corrected

* [C++] Code style modifications

* [C++] Fix flatc arguments in CMakeLists

* [C++] Remove --gen-compare from default parameters for flatc in CMakeLists

* [C++] Change Vector3D fields from double to float, to have alignment eq. 4 (to support MSVC 2010), plus minor review fix

* [C++] Remove one more #if !defined

* [C++] Restore version with correct static_cast, add the same fix for SortedStructs

* Revert "[C++] Restore version with correct static_cast, add the same fix for SortedStructs"

This reverts commit d61f4d6628.

* [C++] Fix Android.mk

BUILD

@@ -137,6 +137,8 @@ cc_test(
         "src/util.cpp",
         "tests/namespace_test/namespace_test1_generated.h",
         "tests/namespace_test/namespace_test2_generated.h",
+        "tests/native_type_test_impl.h",
+        "tests/native_type_test_impl.cpp",
         "tests/test.cpp",
         "tests/test_assert.cpp",
         "tests/test_assert.h",
@@ -168,12 +170,17 @@ cc_test(
         ":tests/arrays_test.bfbs",
         ":tests/arrays_test.fbs",
         ":tests/arrays_test.golden",
+        ":tests/native_type_test.fbs",
+    ],
+    includes = [
+        "include/",
+        "tests/",
     ],
-    includes = ["include/"],
     deps = [
         ":monster_extra_cc_fbs",
         ":monster_test_cc_fbs",
         ":arrays_test_cc_fbs",
+        ":native_type_test_cc_fbs",
     ],
 )
 
@@ -206,3 +213,13 @@ flatbuffer_cc_library(
         "--cpp-ptr-type flatbuffers::unique_ptr",
         "--scoped-enums" ],
 )
+
+flatbuffer_cc_library(
+    name = "native_type_test_cc_fbs",
+    srcs = ["tests/native_type_test.fbs"],
+    flatc_args = [
+        "--gen-object-api",
+        "--gen-mutable",
+        "--cpp-ptr-type flatbuffers::unique_ptr" ],
+)
+