Adds new frame-format variables and implements them in the CPlusPlusLanguage plugin.

We use the `DemangledNameInfo` type to retrieve the necessary part of the demangled name.

https://github.com/llvm/llvm-project/pull/131836

When a frame is inlined, LLDB will display its name in backtraces as
follows:
```
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.3
  * frame #0: 0x0000000100000398 a.out`func() [inlined] baz(x=10) at inline.cpp:1:42
    frame #1: 0x0000000100000398 a.out`func() [inlined] bar() at inline.cpp:2:37
    frame #2: 0x0000000100000398 a.out`func() at inline.cpp:4:15
    frame #3: 0x00000001000003c0 a.out`main at inline.cpp:7:5
    frame #4: 0x000000026eb29ab8 dyld`start + 6812
```
The longer the names get the more confusing this gets because the first
function name that appears is the parent frame. My assumption (which may
need some more surveying) is that for the majority of cases we only care
about the actual frame name (not the parent). So this patch removes all
the special logic that prints the parent frame.

Another quirk of the current format is that the inlined frame name does
not abide by the `${function.name-XXX}` format variables. We always just
print the raw demangled name. With this patch, we would format the
inlined frame name according to the `frame-format` setting (see the
test-cases).

If we really want to have the `parentFrame [inlined] inlinedFrame`
format, we could expose it through a new `frame-format` variable (e..g.,
`${function.inlined-at-name}` and let the user decide where to place
things.

We need to iterate through the all symbol context ranges returned by
(since #126505) SymbolContext::GetAddressRange. This also includes a fix
to print the function offsets as signed values.

I've also wanted to check that the addresses which are in the middle of
the function do *not* resolve to the function, but that's not entirely
the case right now. This appears to be a separate issue though, so I've
just left a TODO for now.

The command already supported disassembling multiple ranges, among other
reasons because inline functions can be discontinuous. The main thing
that was missing was being able to retrieve the function ranges from the
top level function object.

The output of the command for the case where the function entry point is
not its lowest address is somewhat confusing (we're showing negative
offsets), but it is correct.

Many uses of SC::GetAddressRange were not interested in the range, but
in the address of the function/symbol contained inside the symbol
context. They were getting that by calling the GetBaseAddress on the
returned range, which worked well enough so far, but isn't compatible
with discontinuous functions, whose address (entry point) may not be the
lowest address in the range.

To resolve this problem, this PR creates a new function whose purpose is
return the address of the function or symbol inside the symbol context.
It also changes all of the callers of GetAddressRange which do not
actually care about the range to call this function instead.

We still have GetDescription and DumpStopContext which serve a similar
purpose.

(The main reason this is bothering me is because I'm working through the
uses of (deprecated) Function::GetAddressRange.)

Many calls to Function::GetAddressRange() were not interested in the
range itself. Instead they wanted to find the address of the function
(its entry point) or the base address for relocation of function-scoped
entities (technically, the two don't need to be the same, but there's
isn't good reason for them not to be). This PR creates a separate
function for retrieving this, and changes the existing
(non-controversial) uses to call that instead.

The problem here is the assumption that the entire function will be
placed in a single section. This will ~never be the case for a
discontinuous function, as the point of splitting the function is to let
the linker group parts of the function according to their "hotness".

The fix is to change the offset computation to use file addresses
instead.

Signed-off-by: AbdAlRahman Gad <abdobngad@gmail.com>
Co-authored-by: Adrian Prantl <adrian.prantl@gmail.com>

This patch removes all of the Set.* methods from Status.

This cleanup is part of a series of patches that make it harder use the
anti-pattern of keeping a long-lives Status object around and updating
it while dropping any errors it contains on the floor.

This patch is largely NFC, the more interesting next steps this enables
is to:
1. remove Status.Clear()
2. assert that Status::operator=() never overwrites an error
3. remove Status::operator=()

Note that step (2) will bring 90% of the benefits for users, and step
(3) will dramatically clean up the error handling code in various
places. In the end my goal is to convert all APIs that are of the form

`    ResultTy DoFoo(Status& error)
`
to

`    llvm::Expected<ResultTy> DoFoo()
`
How to read this patch?

The interesting changes are in Status.h and Status.cpp, all other
changes are mostly

` perl -pi -e 's/\.SetErrorString/ = Status::FromErrorString/g' $(git
grep -l SetErrorString lldb/source)
`
plus the occasional manual cleanup.