It seems like controlToClass variable is not used anymore.
As it allocates in init we should remove it.
Before:
init golang.org/x/text/unicode/bidi @0.70 ms, 0.003 ms clock, 272 bytes, 2 allocs
After:
init golang.org/x/text/unicode/bidi @0.79 ms, 0 ms clock, 0 bytes, 0 allocs

Change-Id: I79b236feb841c45908431cdb440bd1f4eb082d00
Reviewed-on: https://go-review.googlesource.com/c/text/+/449595
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>