scipy#17783)

Closes scipy#17775

The definition of check_malloc takes a size_t argument.
Fixes a lto-type-mistatch warning.
Related to scipy#16098

…ipy#17800)

* MAINT: Fix wrong 'directed' being passed in the tests for shortest path algorithms
* BUG: scipy.sparse.csgraph: Fix a bug in FibonacciHeap used for the dijkstra function
* TST: PR 17800 revisions to pin down exact test cases

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Co-authored-by: Tyler Reddy <tyler.je.reddy@gmail.com>
Co-authored-by: CJ Carey <perimosocordiae@gmail.com>
Co-authored-by: Kai Striega <kaistriega@gmail.com>

Remove unnecessary reset of dist_array during Bellman-Ford
weight updates.
Add unit test for negative weighted shortest paths.
See scipy#14980

* `\U` leads to strings being treated as unicode, hence we escape it
  with raw strings
* Changed bool parameters real bools instead of string `"True"` and
  `"False"`

[wheel build]

[skip ci]

* test wheel builds in scipygh-18001

[wheel build]