Revert "Android: Fix fat lib toolchain in Trichrome."

This reverts commit a2c39735.

Reason for revert: https://crbug.com/935964

Original change's description:
> Android: Fix fat lib toolchain in Trichrome.
> 
> Missed in https://crrev.com/c/1481019. Only causes errors when
> resource whitelisting is enabled.
> 
> Tbr: agrieve@chromium.org
> Bug: 935088
> Change-Id: Ide099850512681bc6494995310e6c63ac7441365
> Reviewed-on: https://chromium-review.googlesource.com/c/1485232
> Reviewed-by: Eric Stevenson <estevenson@chromium.org>
> Commit-Queue: Eric Stevenson <estevenson@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#634979}

TBR=agrieve@chromium.org,estevenson@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 935088, 935964
Change-Id: Ica482153d538741a0b65828dde0e84e28416283d
Reviewed-on: https://chromium-review.googlesource.com/c/1490515Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635776}

chrome/android/BUILD.gn

@@ -1121,7 +1121,7 @@ if (current_toolchain == default_toolchain) {
 
       generate_resource_whitelist(_resource_whitelist_target) {
         _fat_lib_toolchain = ""
-        if (_is_monochrome || _is_trichrome) {
+        if (_is_monochrome) {
           # Always use the 32-bit library's whitelist since the 64-bit one is
           # webview-only.
           if (!android_64bit_target_cpu) {