Integrate interpreter frames into backtraces (#23973)
Before:
```
julia> let
error()
end
ERROR:
Stacktrace:
[1] error() at ./error.jl:44
```
After:
```
julia> let
error()
end
ERROR:
Stacktrace:
[1] error() at ./error.jl:44
[2] macro expansion at REPL[0]:2 [inlined]
[3] In toplevel scope
```
The extra `macro expansion` frame is a pre-existing julia bug (#23971)
that this PR doesn't address.
The mechanism used here is to add a no-inline enter_interpreter stack frame that has
a known stack layout (since it only has one local variable) and can thus be used
to retrieve the interpreter state. I do not believe that this is guaranteed by the
C standard, so depending on the whims of the compiler we may have to eventually write
this function in assembly, but it seems to work well enough for now.
One significant complication is that the backtrace buffer may now contain pointers
to gc-managed data, so we need to make the gc aware that and can't be as non-chalant
about copying the buffer around anymore.
