Update CpuInfoReader to compute normalized available CPU frequency.

- Guard against reading CpuInfos too frequently.
- Implement dump logic in CpuInfoReader.
- Guard against zero time value in the time_in_state file.

Test: atest CpuInfoReaderTest
Bug: 242722241
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:67bc88121775785907a3aebd87db7c4bdef5fff9)
Merged-In: I9fc109c43fe0bd5f1d16135ad3167325ae502e15
Change-Id: I9fc109c43fe0bd5f1d16135ad3167325ae502e15