This reverts commit 6e45341.

Not all platforms support precisely locating the `symbol_address` for a
frame which means that this test only works on platforms which do.

Looks like finding the enclosing function either isn't fully implemented
or is buggy or something like that. In any case it's not working well
enough that we can test it.

Finding the enclosing function doesn't work there either

This was first introduced with the very first implementation of
symbolication way back when in
rust-lang/rust@bdd31b3, but nowadays
it's not entirely clear that this is still necessary. In any case it's
best to have the adjustment done in symbolication code rather than the
return value of `Frame::ip`, so switch to returning an unadjusted
instruction address.

If this causes issues we can always have some offsets later on in the
return values!

Don't adjust the IP with libunwind

Just an internal refactoring before more are added.

Almost all platforms should still have some degree of symbolication
without debug symbols being present (aka the dynamic symbol table and
such), so add a test asserting that symbols do indeed come out in these
scenarios.

This test will likely need to be blacklisted for platforms over time,
but that's ok.

WIP for rust-lang/rust#61416

Almost all platforms should still have some degree of symbolication
without debug symbols being present (aka the dynamic symbol table and
such), so add a test asserting that symbols do indeed come out in these
scenarios.

This test will likely need to be blacklisted for platforms over time,
but that's ok.

Currently CoreSymbolication will fall back to `dladdr` but this also
applies the same logic to the `libbacktrace` symbolication strategy
since libbacktrace (especially on OSX) can't always get symbol name
information. Instead these platforms will all fall back to `dladdr` if
no symbol information is learned from libbacktrace.

This involved some refactoring internally since all invocations calling
the `dladdr` function are now shared instead of having three separate
ones throughout.

Fall back to `dladdr` on Unix in more places