Create tests for godeltaprof/http/pprof

[korniltsev]

#118

The fact that we use 1.19 in our go.work complicates things - I think it sets httpmuxgo121=1 and it does not panic. So the reproducer for 118 should be for both cases httpmuxgo121=1/0 and probably for go pre 1.21 just in case