Some recent change made isearch to misbehave.

isearch works normally when enable-recursive-minibuffers is off and no
input method is set.

However, when both enable-recursive-minibuffers is on and some input
method is set, pressing C-s and then entering some text does not start a
search. Successive presses of C-s lead to some garbled content being
produced in minibuffer window (see screenshot).

Steps to reproduce.

1. emacs -Q
2. M-x set-input-method RET programmer-dvorak
3. M-x customize-option RET enable-recursive-minibuffers
Toggle the option into "On" state
4. Inside, for example, *scratch* buffer press C-s, then enter text to
search. Observe that interactive search doesn't start. Also, successive
presses of C-s produce some garbled text in minibuffer window as can be
seen on screenshot below.