extdebug now implies errtrace which implies `trap ... ERR` execution w/out `set -e`

[Mike Frysinger]

this set of changes between bash-4.3 & bash-4.4:
https://git.savannah.gnu.org/cgit/bash.git/commit/?h=814e1ff513ceca5d535b92f6c8dd9af7554fe83e

has this buried nugget:
+       - shopt_set_debug_mode: make sure error_trace_mode reflects the setting
+         of extdebug.  This one is tentative.  Fix from Grisha Levit
+         <grishalevit@gmail.com>
+       - shopt_set_debug_mode: call set_shellopts after setting 
error_trace_mode
+         or function_trace_mode.  Fix from Grisha Levit <grishalevit@gmail.com>

which i'm guessing means this behavior is intentional:
$ bash-4.3 -c 'shopt -p -o | grep err; shopt -s extdebug; shopt -p -o | grep 
err'
set +o errexit
set +o errtrace
set +o errexit
set +o errtrace
$ bash-4.4 -c 'shopt -p -o | grep err; shopt -s extdebug; shopt -p -o | grep 
err'
set +o errexit
set +o errtrace
set +o errexit
set -o errtrace

we're in the process of upgrading from bash-4.3 to bash-4.4 and it broke
our build scripts because we use `trap ... ERR` with `shopt -s extdebug`,
but we also toggle `set +e` in a few places to avoid trapping.  that is
no longer sufficient, and now we have to do `set +eE` and `set -eE`.

example shell script showing change in behavior:
$ cat test.sh
#!/bin/bash
foo() {
  false
  return 0
}
shopt -s extdebug
trap 'echo invalid trap; exit 1' ERR
foo
echo "pass"
$ bash-4.3 ./test.sh
pass
$ bash-4.4 ./test.sh
invalid trap

the manual text for extdebug didn't change between the versions, so it's
not clear if this is overall intended as a bug fix.
-mike