Allow build ChromeDriver during Android build

While build for android, ChromeDriver can be built using host toolchain.

Bug: 1050709
Change-Id: Ifc7b97f4474e73e3025ec33450bdfd29559ba087
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2050872Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741146}

BUILD.gn

@@ -496,6 +496,7 @@ group("gn_all") {
       "//base:build_utf8_validator_tables",
       "//base:check_example",
       "//cc:cc_perftests",
+      "//chrome/test/chromedriver:chromedriver($host_toolchain)",
       "//components:components_perftests",
       "//device:device_unittests",
       "//gin:gin_shell",
@@ -514,7 +515,6 @@ group("gn_all") {
       deps += [
         "//chrome/test:load_library_perf_tests",
         "//chrome/test:sync_performance_tests",
-        "//chrome/test/chromedriver:chromedriver",
         "//courgette:courgette",
         "//courgette:courgette_fuzz",
         "//courgette:courgette_minimal_tool",