Revert "Switch the Linux official build to PGO (from AFDO)."

This reverts commit 4be5a8c2.

Reason for revert: Breaks lacros builder https://ci.chromium.org/p/chrome/builders/ci/chromeos-amd64-generic-lacros-builder-perf/2124

Original change's description:
> Switch the Linux official build to PGO (from AFDO).
> 
> This switches the Linux official build from AFDO to PGO. This yield some
> 3-4% performance gains on Speedometer and help unifying our desktop
> build configurations, PGO is already used on Win and Mac. The PGO
> profiles for Linux are generated by a continuous bot and are rolled in
> Chrome once or twice per day (AFDO is based on the Android profiles).
> 
> This increases binary size by ~3-4%.
> 
> Bug: 1111437
> Change-Id: I565eb336fa5ad9480e99808ed49246634255b82d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2404620
> Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#809040}

TBR=thakis@chromium.org,sebmarchand@chromium.org

Change-Id: I774e6ec7877fd255b117f38898d5c91e7c0e4fc0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1111437
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2422253Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809103}

build/config/compiler/BUILD.gn

@@ -89,7 +89,7 @@ declare_args() {
   # nonsensical for said projects.
   clang_use_default_sample_profile =
       chrome_pgo_phase == 0 && build_with_chromium && is_official_build &&
-      is_android
+      (is_android || is_desktop_linux)
 
   # This configuration is used to select a default profile in Chrome OS based on
   # the microarchitectures we are using. This is only used if

build/config/compiler/pgo/pgo.gni

@@ -9,7 +9,7 @@ declare_args() {
   #     1 : Used during the PGI (instrumentation) phase.
   #     2 : Used during the PGO (optimization) phase.
   chrome_pgo_phase = 0
-  if (is_official_build && (is_win || is_mac || (is_linux && !is_chromeos))) {
+  if (is_official_build && (is_win || is_mac)) {
     chrome_pgo_phase = 2
   }