Less xreplace

[finsberg]

Carry over more of the underlying expression. Until now for example the expression

(v - 4.823)/51.12

will silently be turned into

0.0195618153364632*v - 0.0943466353677621

Now, the full expression is carried through the code generation which will hopefully improve the precision.
This is achieved using the context manager

with sp.core.parameters.evaluate(False):
     ....

when using xreplace.

Also remove expressions such as *1.0 and /1.0

[codspeed-hq]

Merging this PR will not alter performance

✅ 8 untouched benchmarks

---

_{Comparing less-xreplace (479bf95) with ode2cellml (2eed77a)¹}

Footnotes

1. No successful run was found on ode2cellml (479bf95) during the generation of this report, so 87644fa was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩