install-build-deps: Remove redundant dev_list

Logic was added to select the right package, based on packages available
within the distro, but the final dev list assignment overwrote what was
selected based on distro.  This results in a breakage for Ubuntu based
builders that still utilize the older package.

Bug: 1122846
Test: './install-build-deps on Ubuntu'
Change-Id: Ia96d29c2b2767bb3a22b002cfba97a9525d246e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2386659
Commit-Queue: Mike Nichols <mikenichols@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803302}

build/install-build-deps.sh

@@ -233,8 +233,6 @@ if file -L /sbin/init | grep -q 'ELF 64-bit'; then
   elif package_exists lib32gcc1; then
     dev_list="${dev_list} lib32gcc1"
   fi
-
-  dev_list="${dev_list} libc6-i386 lib32gcc-s1 lib32stdc++6"
 fi
 
 # Run-time libraries required by chromeos only