uv_run_tests.exe fails to start up with exit code 0xC0000135 a.k.a.
STATUS_DLL_NOT_FOUND, suggesting it cannot find the ASAN runtime
libraries. Disable the buildbot until we figure out how to fix that.
Refs: https://github.com/libuv/libuv/issues/4210
Fixes a detected error: incompatible pointer to integer conversion
passing 'uv_os_fd_t' (aka 'void *') to parameter of type 'SOCKET' (aka
'unsigned long long').
Use upstream llvm to work-around broken VS2022 clang unable to link.
