compiler: in Sort_bindings return false if comparing value to itself
compiler: in Sort_bindings return false if comparing value to itself

Some versions of std::sort may pass elements at the same iterator location.

Fixes golang/go#53483

Change-Id: I2dd04707af3c886e39c59387c955ac5f01932b61
GitHub-Last-Rev: aa751ed0b653bf01e89b4432b198dd38c2eadf72
GitHub-Pull-Request: golang/gofrontend#9
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/413434
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@google.com>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: Cherry Mui <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>

golang/gofrontend,golang/gofrontend,golang/gofrontend,golang/gofrontend