test(inplace_interpolation.jl): check for approx equality

[characat0]

Checklist

• [ ] Appropriate tests were added
• [ ] Any code changes were done in a way that does not break public API
• [ ] All documentation related to code changes were updated
• [ ] The new code follows the contributor guidelines, in particular the SciML Style Guide and COLPRAC.
• [ ] Any new documentation only uses public API

Additional context

Check for approximate equality instead of exact equality.

julia> versioninfo()
Julia Version 1.10.3
Commit 0b4590a5507 (2024-04-30 10:59 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: macOS (arm64-apple-darwin22.4.0)
  CPU: 12 × Apple M2 Pro
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-15.0.7 (ORCJIT, apple-m1)
Threads: 8 default, 0 interactive, 4 GC (on 8 virtual cores)

[ChrisRackauckas]

Why is this needed? What test was this for?

[characat0]

This test errored in my machine, I've added the specs and since another test in the same file also checks for approx equality I think this might have been what the author had intended

[ChrisRackauckas]

I see. Yes looking at it, it can be dependent on how your CPU gets optimized since SIMD allows for reordering of floating point operations, and (x + y) + z is not equal to x + (y + z) in floating point, and this is the cause of the difference.