Fix dropdown positioning problems on mobile when dir=rtl.
Rolls back changes to place.js from 33dc9b874f74e1bf180f9cb6f3c14d13a0fb7a90
about setting drop down's style.right, and instead always sets style.left.

Fixes #17732, refs #5777 on 1.7 branch.

(cherry picked from commit eecfebfd88c6c56b38b8015f62e2b3ea4ebb9287)
(cherry picked from commit ee2afae79613eed7e8dd0513651661ad0bf54a85)