bprc/test: absl C++ versions less than C++17 are not supported

[liuqinfei]

Describe the bug
When compile brpc/test, it fails with
/usr/include/absl/base/policy_checks.h:81:2: error: #error "C++ versions less than C++17 are not supported."
81 | #error "C++ versions less than C++17 are not supported."
| ^~~~~

To Reproduce
sh config_brpc.sh --with-rdma --headers="/usr/include" --libs="/usr/lib64 /usr/bin"
make -j
cd test
make -j

Expected behavior
succeed to compile brpc/test

Versions
OS: openEuler 24.03 (LTS-SP2)
Compiler: 12.3.1-99.oe2403sp2
brpc: 1.16.0
protobuf: 25.1-12.oe2403sp2
abseil-cpp: 20230802.1-6.oe2403sp2.aarch64

Additional context/screenshots