[QNN EP] Revert workarounds for QNN <= 2.35 (#25479)
### Description
Re-enable tests and remove workarounds that were introduced as part of a QNN <= 2.35.0 upgrade but are no longer necessary.
### Motivation and Context
QNN/QAIRT releases about once a month. As ONNX Runtime adopts these new versions, some number of tests are often found to be impacted.
Consequently, tests are skipped and tolerances are loosened. This change reverts as many of those workarounds as possible that were made for QNN upgrades between 2.17 and 2.35, inclusive.
