Pressing ^D in a non-empty input terminates LLDB. This was due to the fact...

Pressing ^D in a non-empty input terminates LLDB. This was due to the fact that we stack more than one editline instance on top of each other and we still expect CTRL+D to exit the editline instance, but it should only do so when the line is empty. Otherwise it should (and does) delete the character at the cursor.

<rdar://problem/15944703>

llvm-svn: 200489