Revert^2 "Add soong config variable Release_expose_flagged_api"

$(call add_json_str,  Platform_base_os,                  $(PLATFORM_BASE_OS))

$(call add_json_str,  Platform_version_last_stable,      $(PLATFORM_VERSION_LAST_STABLE))

$(call add_json_str,  Platform_version_known_codenames,  $(PLATFORM_VERSION_KNOWN_CODENAMES))

$(call add_json_bool, Release_aidl_use_unfrozen,         $(RELEASE_AIDL_USE_UNFROZEN))

$(call add_json_bool, Release_expose_flagged_api,        $(RELEASE_EXPOSE_FLAGGED_API))

$(call add_json_str,  Platform_min_supported_target_sdk_version, $(PLATFORM_MIN_SUPPORTED_TARGET_SDK_VERSION))