inputflinger: avoid vector<const T>

A container of const T uses std::allocator<const T>, which was an
undocumented libc++ extension that has been removed. See
llvm.org/PR96319.

Bug: http://b/349681543
Test: m inputflinger
Change-Id: I4ea703abd6bfcec5b361b638ee1a63c852854b94
1 file changed