Fix hang after failed yank-media on Android

Fix hang after failed yank-media on Android

* java/org/gnu/emacs/EmacsClipboard.java (getClipboardTargets)
(getClipboardData):

* java/org/gnu/emacs/EmacsSdk11Clipboard.java
(getClipboardTargets, getClipboardData):

* java/org/gnu/emacs/EmacsSdk8Clipboard.java
(getClipboardTargets, getClipboardData): Return string data as
Strings rather than byte arrays.

* src/androidselect.c (android_init_emacs_clipboard)
(Fandroid_get_clipboard_targets): Adjust to match.
(extract_fd_offsets): Remove duplicated semicolon.
(Fandroid_get_clipboard_data): Call unblock_input before
returning if extract_fd_offsets fails.