perf tests: Add robust record retry helper and use subsecond workloads

Introduce `perf_record_with_retry` and `perf_record_cleanup` in a shared
library `tests/shell/lib/perf_record.sh` to prevent record test failures
caused by transient recording or workload delays.

Update `record.sh`, `record_lbr.sh`, `pipe_test.sh`, `kvm.sh`, and
`stat_all_pfm.sh` to use this robust record retry logic. These tests now
start with very short durations (e.g. 0.01 seconds) and scale up if the
initial recording failed to capture samples, significantly improving test
execution speed on success while remaining resilient to slow systems.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

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