We now bubble up the expression evaluation diagnostics to the user and
also distinguish between "expression failed to parse/run" versus other
ways in which expressions didn't complete (e.g., setup errors, etc.).
Before:
```
(lldb) memory find -e "" 0x16fdfedc0 0x16fdfede0
error: expression evaluation failed. pass a string instead
(lldb) memory find -e "invalid" 0x16fdfedc0 0x16fdfede0
error: expression evaluation failed. pass a string instead
```
After:
```
(lldb) memory find -e "" 0x16fdfedc0 0x16fdfede0
error: Expression evaluation failed:
error: No result returned from expression. Exit status: 1
(lldb) memory find -e "invalid" 0x16fdfedc0 0x16fdfede0
error: Expression evaluation failed:
error: <user expression 0>:1:1: use of undeclared identifier 'invalid'
1 | invalid
| ^~~~~~~
```