Remove false assert from get_pointer_to_constant (#63623)
Reported by @mlechu because of this CI failure:
https://buildkite.com/julialang/julia-pr/builds/3441/canvas?jid=01a111ef-f0c4-48e9-aaf3-9b0469ef9e21&tab=output#01a111ef-f0c4-48e9-aaf3-9b0469ef9e21/L1469
Somehow we never hit this before: if two callers of
`get_pointer_to_constant` use different names for the same constant
(say, the same small integer), the assertion about the name will fail
because it will already be in mergedConstants with the other name. This
is totally fine but the assert must be removed.
