Add test case for new floatmin2

Author: dgleich

test/specialvalues.jl

@@ -61,3 +61,8 @@ end
     @test isnan(asech(T(NaN)))
     @test isnan(acoth(T(NaN)))
 end
+    
+@testset "floatmin2" for T in (Double16, Double32, Double64)
+    trueval = (twopar = 2one(T); twopar^trunc(Integer,log(floatmin(T)/eps(T))/log(twopar)/twopar))
+    @test LinearAlgebra.floatmin2(T) == trueval 
+end