Add CPU/GPU_LOAD_SPIKE hints for one-off expensive workloads

Currently there is ambiguity between single-frame expensive ops
(eg: shader compilation) and longer-duration expensive ops (eg:
SF client compositon). This load hint aims to resolve this by
explicitly annotating one-time expensive workloads so they can
be given unique boost and hysteresis expectations.

For example, a load_spike aware tracker might want to ignore
the timing that comes from a LOAD_SPIKE-marked frame, as it is
known to not be representative of the overall workload.

Flag: EXEMPT HAL interface change
Test: atest libadpf_test
Test: atest VtsHalPowerTargetTest
Bug: 367803904

Change-Id: Ifaa5437be4477991cf5a6374acaf500c8aeef3ab