Unit test lower_byte_update of/from an array of bits

Byte operator lowering made several assumptions about array elements
being byte aligned, which may be true for ANSI C, but isn't the case for
our C front-end (which supports arrays of single bits), and not true for
the overall framework in general.

Author: tautschnig

unit/solvers/lowering/byte_operators.cpp

@@ -429,6 +429,7 @@ SCENARIO("byte_update_lowering", "[core][solvers][lowering][byte_update]")
       union_typet({{"compA", u32}, {"compB", u64}}),
       c_enum_typet(u16),
       c_enum_typet(unsignedbv_typet(128)),
+      array_typet{bv_typet{1}, from_integer(128, size_type())},
       array_typet(u8, size),
       array_typet(s32, size),
       array_typet(u64, size),