Revert "Merge pull request #14273 from edx/feanil/test_with_system_firefox"

This reverts commit 04f87694, reversing
changes made to 4b196d42.

scripts/generic-ci-tests.sh

@@ -162,6 +162,12 @@ case "$TEST_SUITE" in
 
     "bok-choy")
 
+        # Back compatibility support for firefox upgrade:
+        # Copy newer firefox version to project root,
+        # set that as the path for bok-choy to use.
+        cp -R $HOME/firefox/ firefox/
+        export SELENIUM_FIREFOX_PATH=firefox/firefox
+
         PAVER_ARGS="-n $NUMBER_OF_BOKCHOY_THREADS --with-flaky --with-xunit"
 
         case "$SHARD" in