[llvm] [llvm-profgen] Filter out ambiguous cold profiles during profile generation (PR #81803)

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WenleiHe wrote:

> > Thanks for looking into alternatives. Actually how about we add another function `FunctionSamples::RemoveCallSamples` to do this? We already have `removeCalledTargetAndBodySample`.
> 
> It'd probably also be hacky if we use an internal `RemoveCallSamples`,
> 
> 1. The current filter is to match a prefix not a exact callsite. the input parameter is a prefix/ or a list of prefix..
> 2. Or we can do a round of lookup for CallSamples to generate a list of `ToBeRemovedFS` Pointer... then pass them to  an internal `RemoveCallSamplesPointer` ... which looks too complicated..

Ok, let's just use the current for now then. 

https://github.com/llvm/llvm-project/pull/81803