Remove the extraneous disable_compact unwind tests.

These were copied over from the libunwind test suite and are essentially
duplicates of the unwind_test_x86_frame.S/unwind_test_x86_64_frame.S
test cases; the only difference is that compact unwind encoding
generation is disabled for disable_compact_frame variants.

We're able to test DWARF unwinding in isolation without using completely
distinct test data; our frame reading API allows callers to supply the
specific unwinder implementations to be used at each stage of the unwind
process.

As a result, we don't need these (essentially duplicate) frame unwinding
test cases; removing them reduces the work necessary to ensure that we
supply a __LD,__compact_unwind section for all of our test cases (which
is necessary to avoid linker warnings regarding its inability to
translate unsupported DWARF constructs to a compact unwind
representation).

Issue: PLCR-541