suggestions for laed4

[langou]

@BrianDang03

Please use <T>LAPACK slice operator to slice vector, do not use the std::vector() extraction feature https://github.com/tlapack/tlapack/blob/f27c8ccbcca34360b433641de97bc1d3c1100cd4/include/tlapack/lapack/laed4.hpp#L609 https://github.com/tlapack/tlapack/blob/f27c8ccbcca34360b433641de97bc1d3c1100cd4/include/tlapack/lapack/laed4.hpp#L795

Also, since we are at it, please remove: https://github.com/tlapack/tlapack/blob/f27c8ccbcca34360b433641de97bc1d3c1100cd4/include/tlapack/lapack/laed4.hpp#L116

Also let us remove these commented lines: https://github.com/tlapack/tlapack/blob/f27c8ccbcca34360b433641de97bc1d3c1100cd4/test/src/test_laed4.cpp#L151-L239C1

Also, please add a TODO: TO REMOVE here https://github.com/tlapack/tlapack/blob/f27c8ccbcca34360b433641de97bc1d3c1100cd4/test/src/test_laed4.cpp#L140 so that we remember that there is an issue here.