scripts: csv.py: Tweaked --list-computed to infer all input field types

On one hand, only inferring the used input fields is conceptually
correct because that's how csv.py works. On the other, it doesn't really
make sense for --list-computed to show _less_ information than
--list-fields.

So, showing all inferred types now:

  $ ./scripts/csv.py --list-computed test.csv \
        -bcase='%(case)s+%(m)s' \
        -fsimtime='float(bench_simtime)/1.0e9' \
        -fsimthroughput='float(n)/max(float(bench_simtime)/1.0e9,1.0e-9)'
  i              int   .-->  case           ?    ?
  suite          ?     |.->  simtime        int  sum
  case           ?    -+|.>  simthroughput  int  sum
  SKIP_WARMUP    int   |||
  FILE_SIZE      int   |||
  SEED           int   |||
  ...
  m              ?    -'||
  n              int  ---+
  bench_reads    int    ||
  bench_progs    int    ||
  bench_erases   int    ||
  bench_readed   int    ||
  bench_progged  int    ||
  bench_erased   int    ||
  bench_simtime  int  ---'

I think this makes --list-computed a strict superset of --list-fields
now.

scripts/csv.py

@@ -2391,11 +2391,34 @@ def list_fields(csv_paths, **args):
     for k, t in zip(fields_, types__):
         print('%-*s  %s' % (w[0], k, t))
 
-def list_computed(Result, **args):
-    # figure out input fields and types, these are stashed in the
-    # compiled Result type for this sort of introspection
-    fields_ = Result._fields_
-    types_ = Result._types_
+def list_computed(fields_, results, Result, **args):
+    # find best type for fields, note this matches compile behavior
+    types_ = {}
+    for k in fields_:
+        try:
+            for t in [CsvInt, CsvFloat, CsvFrac]:
+                for r in results:
+                    if k in r and r[k].strip():
+                        try:
+                            t(r[k])
+                        except ValueError:
+                            break
+                else:
+                    types_[k] = t
+                    break
+        except AttributeError:
+            pass
+
+    # find best name for types
+    types__ = []
+    for k in fields_:
+        if k in types_:
+            t = types_[k].__name__
+            if t.startswith('Csv'):
+                t = t[len('Csv'):]
+            types__.append(t.lower())
+        else:
+            types__.append('?')
 
     # find best name for types
     types__ = []
@@ -2699,7 +2722,7 @@ def main(csv_paths, *,
 
     # list computed?
     if args.get('list_computed'):
-        return list_computed(Result, **args)
+        return list_computed(fields_, results, Result, **args)
 
     # homogenize
     results = homogenize(Result, results,