remove vptr sanitize because it's not included in future features

If `vptr` is enabled, the following errors are raised
during build steps because the vptr sanitizer requires
RTTI, but RTTI is disabled (by default).

```
[397/398] Linking C executable src/suggest/groonga-suggest-create-dataset
FAILED: src/suggest/groonga-suggest-create-dataset
: && /usr/bin/clang -fsanitize=undefined -fno-sanitize=alignment -g  src/suggest/CMakeFiles/groonga-suggest-create-dataset.dir/groonga_suggest_create_dataset.c.o -o src/suggest/groonga-suggest-create-dataset  -Wl,-rpath,/groonga.ubsan/lib:/groonga.ubsan/_deps/llama_cpp-build/src:/groonga.ubsan/_deps/llama_cpp-build/ggml/src:  lib/libgroonga.so.0.0.0  /usr/lib/x86_64-linux-gnu/libmsgpackc.so.2.0.0  _deps/llama_cpp-build/src/libgroonga-llama.so.0.0.0  _deps/llama_cpp-build/ggml/src/libgroonga-ggml.so.0.0.0  _deps/llama_cpp-build/ggml/src/libgroonga-ggml-base.so.0.0.0 && :
/usr/bin/ld: lib/libgroonga.so.0.0.0: undefined reference to `__ubsan_vptr_type_cache'
/usr/bin/ld: lib/libgroonga.so.0.0.0: undefined reference to `__ubsan_handle_dynamic_type_cache_miss'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```

llvm/llvm-project#121115

Author: otegami

CMakeLists.txt

@@ -525,21 +525,10 @@ option(GRN_WITH_UBSAN "Enable Undefined Behavior Sanitizer (UBSAN) checking"
        OFF)
 if(GRN_WITH_UBSAN)
   if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
-    set(GRN_UBSAN_FLAGS "-fsanitize=undefined -fno-sanitize=alignment")
+    set(GRN_UBSAN_FLAGS "-fsanitize=undefined -fno-sanitize=alignment,vptr")
     string(APPEND CMAKE_C_FLAGS " ${GRN_UBSAN_FLAGS}")
     string(APPEND CMAKE_CXX_FLAGS " ${GRN_UBSAN_FLAGS}")
     message(STATUS "UBSAN flags: ${GRN_UBSAN_FLAGS}")
-    execute_process(
-      COMMAND ${CMAKE_C_COMPILER}
-              -print-file-name=libclang_rt.ubsan_standalone-x86_64.so
-      OUTPUT_VARIABLE GRN_UBSAN_LIB_PATH
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
-    if(GRN_UBSAN_LIB_PATH)
-      string(APPEND CMAKE_EXE_LINKER_FLAGS " ${GRN_UBSAN_LIB_PATH}")
-      message(STATUS "Found UBSAN runtime library: ${GRN_UBSAN_LIB_PATH}")
-    else()
-      message(FATAL_ERROR "No UBSAN runtime library found")
-    endif()
   else()
     message(FATAL_ERROR "UBSAN support is available only for Clang")
   endif()