Add ZX dependency in googletest

Add explicit dependency on fuchsia-sdk:zx in googletest. This should
unblock chromium roll to V8, which was broken after crrev.com/607798

TBR=dpranke@chromium.org

Bug: 893369
Change-Id: I58895fce6d2ed40008cac724735403be8b70226d
Reviewed-on: https://chromium-review.googlesource.com/c/1336070Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608025}

third_party/googletest/BUILD.gn

@@ -129,7 +129,10 @@ source_set("gtest") {
   }
 
   if (is_fuchsia) {
-    deps += [ "//third_party/fuchsia-sdk/sdk:fdio" ]
+    deps += [
+      "//third_party/fuchsia-sdk/sdk:fdio",
+      "//third_party/fuchsia-sdk/sdk:zx",
+    ]
   }
 }