set +E after shopt -s extdebug

Since bash-4.4, `shopt -s extdebug` implies `set -E`.
Adding set +E after shopt to revert it.

https: //lists.gnu.org/archive/html/bug-bash/2021-02/msg00066.html

BUG=None
TEST=unit tests

Change-Id: I9bc92f1799469546930ce3237f0edc3a02630c83
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2684668
Tested-by: Sergey Frolov <sfrolov@google.com>
Commit-Queue: Sergey Frolov <sfrolov@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/common.sh b/common.sh
index b14bcde..2b8f985 100644
--- a/common.sh
+++ b/common.sh
@@ -44,6 +44,7 @@
 
 # Turn on bash debug support if available for backtraces.
 shopt -s extdebug 2>/dev/null
+set +E
 
 # Output a backtrace. Optional parameter allows hiding the last
 # frame(s) so functions like "die()" can hide their additional