Support Go 1.26: internal/itoa removed (replaced by internal/strconv)

[sivchari]

Go 1.26 removed the internal/itoa package from the standard library. This causes TinyGo build failures when using Go 1.26. This problem is caused sinceinternal/itoa was removed in golang/go@49c1da4
So I propose

1. Add src/internal/itoa/itoa.go to tinygo source
2. Update "internal/itoa": false to pathsToOverride()

What do you think ?

[b0ch3nski]

There is an ongoing effort for 1.26 support here: #5166

[sivchari]

Great, it's what I need.