Roll gn from 97b68a0bb62b to 635a71e20e99

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Cq-Include-Trybots: luci.dart.try:dart-sdk-linux-try;luci.dart.try:dart-sdk-mac-try;luci.dart.try:dart-sdk-mac-arm64-try;luci.dart.try:dart-sdk-win-try
Change-Id: Idbc105056af9f47b63362d07f4fb6f7cad13f596
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/438460
Reviewed-by: Alexander Markov <[email protected]>
Reviewed-by: Alexander Aprelev <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>

Author: DEPS Autoroller

DEPS

@@ -78,7 +78,7 @@ vars = {
   "clang_version": "git_revision:8c7a2ce01a77c96028fe2c8566f65c45ad9408d3",
 
   # https://chrome-infra-packages.appspot.com/p/gn/gn
-  "gn_version": "git_revision:97b68a0bb62b7528bc3491c7949d6804223c2b82",
+  "gn_version": "git_revision:635a71e20e99db0b08520ca0746b501167a5c7e5",
 
   "reclient_version": "re_client_version:0.178.0.5ee9d3e8-gomaip",
   "download_reclient": True,