Revert "compiler: remove `!is_android` from CrOS thinlto checks"

This reverts commit 5c44b2a9.

Reason for revert:
cros_browser_sanity_test failures beginning in https://ci.chromium.org/p/chrome/builders/ci/chromeos-betty-pi-arc-cfi-thin-lto-chrome/361. Only the ThinLTO bot is failing, which make me suspicious of this change.

Original change's description:
> compiler: remove `!is_android` from CrOS thinlto checks
> 
> This was originally added for linux-chromeos builds. Now that we have
> is_chromeos_device here, it's redundant, and it unintentionally disables
> ThinLTO/CFI for ARC pieces of non-linux CrOS builds.
> 
> Bug: 1062713, 1050199
> Change-Id: I27022ed72597a90ae7d2bb385729550fa8d772e6
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2108822
> Reviewed-by: Bob Haarman <inglorion@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Reviewed-by: Ben Pastene <bpastene@chromium.org>
> Commit-Queue: George Burgess <gbiv@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#751505}

TBR=thakis@chromium.org,gbiv@chromium.org,bpastene@chromium.org,inglorion@chromium.org

Change-Id: I57aafeaa0e4f6bb60c22f8ea0b085282869fffd7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1062713, 1050199
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2109752Reviewed-by: Mike West <mkwst@chromium.org>
Commit-Queue: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751629}

build/config/compiler/compiler.gni

@@ -69,9 +69,10 @@ declare_args() {
   # Use it by default on official-optimized android and Chrome OS builds, but
   # not ARC or linux-chromeos since it's been seen to not play nicely with
   # Chrome's clang. crbug.com/1033839
-  use_thin_lto = is_cfi || (is_official_build &&
-                            (target_os == "android" ||
-                             (target_os == "chromeos" && is_chromeos_device)))
+  use_thin_lto =
+      is_cfi || (is_official_build && (target_os == "android" ||
+                                       (target_os == "chromeos" &&
+                                        is_chromeos_device && !is_android)))
 
   # Performs ThinLTO code generation on Goma.
   use_goma_thin_lto = false

build/config/sanitizers/sanitizers.gni

@@ -57,7 +57,7 @@ declare_args() {
   # crbug.com/1033839. Similarly, don't use this on ARC builds.
   is_cfi = is_official_build &&
            ((target_os == "linux" && !is_chromeos && target_cpu == "x64") ||
-            (target_os == "chromeos" && is_chromeos_device))
+            (target_os == "chromeos" && is_chromeos_device && !is_android))
 
   # Enable checks for indirect function calls via a function pointer.
   # TODO(pcc): remove this when we're ready to add these checks by default.