Resolve stack-overflow in Diagonal*Bidiagonal and (Sym)Tridiagonal

[jishnub]

Currently, there are method ambiguities on v1.10, because of which these paths were not being tested. These ambiguities are resolved on the currently nightly, which reveals a stack-overflow in these methods. This arises because an operation like

(D::Diagonal{<:Any, <:LayoutVector}) * (B::Bidiagonal{<:Any, <:LayoutVector})

internally calls

copy(M::Lmul{<:DiagonalLayout,<:BidiagonalLayout})

but this method was calling D * B again, leading to a cycle. To avoid this, we now broadcast D.diag over the other matrix. The added tests all work on nightly where there are no method ambiguities anymore, and the Bidiagonal ones work on current versions as well.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 23 lines in your changes missing coverage. Please review.

Project coverage is 0.00%. Comparing base (d315ce3) to head (77bfc17).

Files	Patch %	Lines
src/diagonal.jl	0.00%	23 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (d315ce3) and HEAD (77bfc17). Click for more details.

HEAD has 7 uploads less than BASE

Flag	BASE (d315ce3)	HEAD (77bfc17)
	12	5

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #242       +/-   ##
==========================================
- Coverage   90.43%   0.00%   -90.44%     
==========================================
  Files          11      11               
  Lines        1902    1814       -88     
==========================================
- Hits         1720       0     -1720     
- Misses        182    1814     +1632     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.