all: drop pre go1.16 versions (and unicode tables)

This removes most of the tables that were only supported by older go version,
which was added in c4d099d
(https://go-review.googlesource.com/83235)

I kept the "go1.16" build tag for now, but this can probably be dropped.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

cases/tables10.0.0.go

@@ -83,10 +83,6 @@ func CLDRVersion() string {
 }
 
 var tags = []struct{ version, buildTags string }{
-	{"9.0.0", "!go1.10"},
-	{"10.0.0", "go1.10,!go1.13"},
-	{"11.0.0", "go1.13,!go1.14"},
-	{"12.0.0", "go1.14,!go1.16"},
 	{"13.0.0", "go1.16"},
 }