Hello Rushabh,
We measuring the IDDQ at top level power pins only as IDDQ is the current from VDD to VSS. We measuring current at VDD or VSS. There are some special circuits available to measure current. Either in chip or supported by ATE, we measure the IDDQ current.
If yoy want to ask about at which point IDDQ measured, than please do not use Fault location word. As in DFT, Fault location is doesn't mean that, so people confused more. So please take care while using technical words.