Revert "Fix convert(::Type{<:StaticArray}, ::UniformScaling) (#759)"

This reverts commit f37b58e.

As discussed in #759, `convert` semantics are problematic (convert
should preserve `isequal` `isless`, and `hash`) so revert this for now.

Author: c42f

src/linalg.jl

@@ -102,7 +102,6 @@ end
 # because we do not have `SArray{Tuple{2,3}} <: StaticMatrix`.
 (::Type{SM})(I::UniformScaling) where {SM<:(StaticArray{Tuple{N,M}} where {N,M})} =
     _scalar_matrix(Size(SM), SM, I.λ)
-convert(T::Type{<:StaticArrayLike}, I::UniformScaling) = T(I)
 
 # Construct a matrix with the scalar λ on the diagonal and zeros off the
 # diagonal. The matrix can be non-square.

test/linalg.jl

@@ -75,13 +75,6 @@ using LinearAlgebra: checksquare
         @test @inferred(SDiagonal{3}(2.0I))::SDiagonal{3,Float64} == 2I3x3
         @test @inferred(SDiagonal{3,Float64}(I))::SDiagonal{3,Float64} == I3x3
         @test @inferred(SDiagonal{3,Float32}(2.0I))::SDiagonal{3,Float32} == 2I3x3
-
-        # convert from UniformScaling falls back to constructors
-        @test @inferred(convert(SMatrix{2,2,Float64}, I)) === SA_F64[1 0; 0 1]
-        @test @inferred(convert(MMatrix{2,2,Float64}, I))::MMatrix{2,2,Float64} == SA[1 0; 0 1]
-        @test @inferred(convert(SMatrix{2,2}, I)) === SA{Bool}[1 0; 0 1]
-        @test @inferred(convert(SArray{Tuple{2,2}}, I)) === SA{Bool}[1 0; 0 1]
-        @test @inferred(convert(SDiagonal{2}, I)) === Diagonal{Bool,SArray{Tuple{2},Bool,1,2}}((1,1))
     end
 
     @testset "diagm()" begin