[lldb] Improve error message when evaluating expression when not stopped
When trying to run an expression after a process has existed, you
currently are shown the following error message:
(lldb) p strlen("")
error: Can't make a function caller while the process is running
This error is wrong and pretty uninformative. After this patch, the
following error message is shown:
(lldb) p strlen("")
error: unable to evaluate expression while the process is exited: the
process must be stopped because the expression might require
allocating memory.
rdar://
109731325
Differential revision: https://reviews.llvm.org/D151497