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fix(core): tests for 2-arg Mul restriction #27205

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Updates tests wrt gh-27200. This is built on top of gh-27200 to keep changes to tests separate from the actual behaviour changes.

Brief description of what is fixed or changed

Other comments

Release Notes

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@oscarbenjamin
fix(core): restrict the 2-arg Mul to -1
9e9c4d9 
Since 3e835b5 from sympygh-716 there is the following behaviour:

  >>> 2*(x + y)
  2*x + 2*y

Specifically if there is a Mul with 2 args and one arg is a Rational
and the other an Add then the Rational is distributed into the Add.
More generally if there is a Mul and the arguments collapse to a number
and an Add e.g. Mul(2, 3.0, x + y) then the coefficient is distributed
into the Add.

There are various problems with this behaviour such as the fact that it
breaks associativity (a*b)*c != a*(b*c). There have been previous
attempts to remove this e.g. sympygh-17242 but it is not easy because so much
code now depends on it.

This commit attempts a more limited change in which the 2-arg Mul is
mostly removed but kept for one important special case: if we have
Mul(-1, Add(...)) then the -1 will be distributed into the Add. This
special case is important because it arises when subtracting to Adds
e.g.:

  >>> x + y - (x + y)
  0

It could perhaps be possible to special case negation and subtraction
somehow so that negating the terms of an Add happens specifically in
subtraction rather than more generally in a Mul but here we just
preserve the 2-arg behaviour for -1 specifically as a more limited
change to existing behaviour. Keeping this particular special case of
the 2-arg Mul dramatically reduces the number of test failures seen in
the test suite comared to removing automatic distribution altogether.
@oscarbenjamin
test(ci): Add timeout to normal test run
be24ad9
@oscarbenjamin
fix(simplify): try a bit harder in hypersimp
13818ed
@oscarbenjamin
fix(simplify): use expand_mul in fu/trigsimp
5c2be3d
@oscarbenjamin
test(ci): use timeout in all pytest jobs
a18e1fc
@oscarbenjamin
fix(functions): Use expand_mul in gamma.expand_func
a5332f4
@oscarbenjamin
fix(simplify): check for Expr in exptrigsimp
a47578c
@oscarbenjamin
simplify: use expand_mul for exponents in powsimp
cb44979
@oscarbenjamin
wip
185235d
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Updates tests wrt gh-27200. This is built on top of gh-27200 to keep changes to tests separate from the actual behaviour changes.

#### Brief description of what is fixed or changed


#### Other comments


#### Release Notes

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