Eliminate StreamExecutor::live_stream_count_ as StreamExecutors are never destroyed, and the destructor is never run.
Eliminate StreamExecutor::live_stream_count_ as StreamExecutors are never destroyed, and the destructor is never run.

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/11205 from ROCm:ci_link_break_20240404 8ee9b5e90d4e1a3ca7734bbe1ef73140e4d879dd
