Translator: Fix validation of struct with same-name struct field In the following: ``` struct S { S s; }; ``` The `S` in the field refers to a previous declaration of `S` in an outer scope. The validation code mistakenly attempted to ensure it refers to the same `S` being declared. Bug: chromium:1337628 Change-Id: I86184be63bc59e608fe5b24369cd4c40b3bb3b31 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3716965 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Yuxin Hu <yuxinhu@google.com> Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org>