faster rand(::MersenneTwister, ::Union{[U]Int{8,16,32},Bool}) (#25277)

Now that generating scalar Float64 values (i.e. 52 random bits) is even faster,
it becomes faster to just generate such values and make small integers out of
them, rather than saving entropy bits with using the integer cache.

base/random/RNGs.jl

@@ -313,8 +313,11 @@ rand(r::MersenneTwister, sp::SamplerTrivial{Close1Open2_64}) =
 
 #### integers
 
-rand(r::MersenneTwister, T::SamplerUnion(BitInteger)) = mt_pop!(r, T[])
-rand(r::MersenneTwister, ::SamplerType{Bool}) = rand(r, UInt8) % Bool
+rand(r::MersenneTwister, T::SamplerUnion(Union{Int64,UInt64,Int128,UInt128})) =
+    mt_pop!(r, T[])
+
+rand(r::MersenneTwister, T::SamplerUnion(Union{Bool,Int8,UInt8,Int16,UInt16,Int32,UInt32})) =
+    rand(r, UInt52Raw()) % T[]
 
 #### arrays of floats
 

test/random.jl

@@ -278,10 +278,10 @@ let mt = MersenneTwister(0)
         B = Vector{T}(uninitialized, 31)
         rand!(mt, A)
         rand!(mt, B)
-        @test A[end] == Any[21, 0x4e, -3158, 0x0ded, 2132370312, 0x5e76d222, 1701112237820550475, 0x552ac662d46426bf,
-                            -48946429529471164341432530784191877404, Float16(0.99805), 0.845204f0][i]
-        @test B[end] == Any[94, 0x14, 22684, 0x0278, -862240437, 0xc425026c, -7329373301769527751, 0x8a40806d8107ce23,
-                            37650272825719887492093881479739648820, Float16(0.14648), 0.5025569f0][i]
+        @test A[end] == Any[21, 0x7b, 17385, 0x3086, -1574090021, 0xadcb4460, 6797283068698303107, 0xc8e6453e139271f3,
+                            69855512850528774484795047199183096941, Float16(0.16895), 0.21086597f0][i]
+        @test B[end] == Any[49, 0x65, -3725, 0x719d, 814246081, 0xdf61843a, 2120308604158549401, 0xcb28c236e9c0f608,
+                            61881313582466480231846019869039259750, Float16(0.38672), 0.20027375f0][i]
     end
 
     srand(mt, 0)