[llvm] [profdata] Consume reader error if returned early (PR #163671)

[Ellis Hoag via llvm-commits]

ellishg wrote:

> is it possible to add a small test?

@david-xl we only hit an assert if we early return in one of these places

https://github.com/llvm/llvm-project/blob/68fa9c45f10b13f079a204723407470cba6aa73e/llvm/tools/llvm-profdata/llvm-profdata.cpp#L857-L868

The problem is it is difficult to reproduce these errors in `.profraw` files. The tests `malformed-num-counters-zero.test` and `malformed-ptr-to-counter-array.test` have to manually create `.profraw` files and corrupt them somehow, which involve parsing the byte representation of these files. Ideally we would have some textual representation of `.profraw` files, similar to `.proftext` files. For now, it is pretty difficult to write a test for this.

https://github.com/llvm/llvm-project/pull/163671