[Wextra-semi] Reland of suppress -Wextra-semi in tink

BUILD.gn files in tink/cc are overwritten by running `convert_for_cobalt`
Relanding the Fuchsia-specific commits in the tink BUILD.gn files to
avoid overwrite.

Original commit:
[Wextra-semi]1c99707014c49a89b566383aaaf11e765b5f80df

Bug: b/286923532

Change-Id: I2d69ec5f0a3d0fd9c77fd1ee210b8efece96cb85
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/tink/+/869281
Reviewed-by: Francois Rousseau <frousseau@google.com>
Commit-Queue: Anivia Li <aniviali@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index bf7f4be..383295f 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -11,6 +11,9 @@
 
     # The tink library uses absl headers with implicit copy constructors.
     "-Wno-deprecated-copy",
+
+    # The tink library does not restrict extra semicolon.
+    "-Wno-extra-semi",
   ]
 
   include_dirs = [