-po requires profiled build

Summary

When running a non-profiling built application with the -hT flag it is sometimes helpful to specify where the .hp should go with the -po flag. Yet this will give you the following error.

 the flag -po requires the program to be built with -prof

This made sense when all heap profiling required -prof but now you can run -hT which doesn't require -prof.

So this error should not be thrown.

I noticed this while working on #21446 (closed)

Steps to reproduce

Compile an application without -prof and run app +RTS -hT -postem you will get an error

Expected behavior

No error should be thrown and -po should be respected.

Environment

• GHC version used: 8.10.7