glDeleteQueries() instantly deletes all the es2::Query objects
passed as arguments to this function. If some of these queries
are still being used by the renderer, this will result in a use
after free error. To solve this issue, sw::Query is now a also
ref counted object.

Bug chromium:904714

Change-Id: Ic1d5781bbf1724d8d07936fd49c8a172dc3d9fd4
Reviewed-on: https://swiftshader-review.googlesource.com/c/22548Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>