Fix overflow in pow5 (#47511)

Fixup for #46764

(cherry picked from commit 02aa0b0)

Author: LilithHafner

base/ryu/utils.jl

@@ -64,7 +64,7 @@ lengthforindex(idx) = div(((Int64(16 * idx) * 1292913986) >> 32) + 1 + 16 + 8, 9
 
 Return `true` if `5^p` is a divisor of `x`.
 """
-pow5(x, p) = x % (5^p) == 0
+pow5(x, p) = x % (UInt64(5)^p) == 0
 
 """
     Ryu.pow2(x, p)

test/ryu.jl

@@ -52,6 +52,11 @@ end
     @test "2.305843009213694e40" == Ryu.writeshortest(Core.bitcast(Float64, 0x4850F0CF064DD592))
 end
 
+@testset "pow5 overflow (#47464)" begin
+    @test "4.6458339e+63" == Ryu.writeexp(4.645833859177319e63, 7)
+    @test "4.190673780e+40" == Ryu.writeexp(4.190673779576499e40, 9)
+end
+
 @testset "OutputLength" begin
     @test "1.0" == Ryu.writeshortest(1.0) # already tested in Basic
     @test "1.2" == Ryu.writeshortest(1.2)