[gcmole] Fix BUILD.gn to include compiler directory.

R=clemensh@chromium.org

Change-Id: I8f51731a789b242cdd489f6321bc1ba909aa5d66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1599548Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61311}

BUILD.gn

@@ -1683,6 +1683,7 @@ v8_header_set("v8_shared_internal_headers") {
 }
 
 v8_compiler_sources = [
+  ### gcmole(all) ###
   "src/compiler/access-builder.cc",
   "src/compiler/access-builder.h",
   "src/compiler/access-info.cc",