Run pregenerate as part of run_tests

I keep forgetting to rerun it and CMake often does not notice.

Change-Id: I003f603814f308067b51c2bd95ac5f376ea9b693
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/97527
Reviewed-by: Adam Langley <agl@google.com>
Presubmit-BoringSSL-Verified: boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com <boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Adam Langley <agl@google.com>
Auto-Submit: David Benjamin <davidben@google.com>

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index aaf3bf1..6fcb691 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -828,6 +828,9 @@
     if(GO_EXECUTABLE)
       add_custom_target(
           run_tests
+          COMMAND ${CMAKE_COMMAND} -E echo "Checking pregenerated files"
+          COMMAND ${GO_EXECUTABLE} run ./util/pregenerate -check
+          COMMAND ${CMAKE_COMMAND} -E echo
           COMMAND ${CMAKE_COMMAND} -E echo "Running Go tests"
           COMMAND ${GO_EXECUTABLE} test ${GO_TESTS}
           COMMAND ${CMAKE_COMMAND} -E echo