Investigating Checkpoint naming restrictions in testing:

• Creating a checkpoint with any characters works, however when we attempt to read the checkpoint (or export the metadata for the table) we encounter errors.
• Discovered when working on WT-12030
• Seems similar to C naming conventions

In `test_import01.py` the following diffs raise a `_wiredtiger.WiredTigerError: Invalid argument`

• Checkpoint name starts with a number

  diff --git a/test/suite/test_import01.py b/test/suite/test_import01.py
  index 95624150c..32847a137 100644
  --- a/test/suite/test_import01.py
  +++ b/test/suite/test_import01.py
  @@ -159,6 +159,7 @@ class test_import01(test_import_base):
           for i in range(min_idx, max_idx):
               self.update(self.uri, self.keys[i], self.values[i], self.ts[i])
           self.session.checkpoint()
  +        self.session.checkpoint("name=123")
   
           # Export the metadata for the table.
           c = self.session.open_cursor('metadata:', None, None)

• Checkpoint name starts with a hyphen

  diff --git a/test/suite/test_import01.py b/test/suite/test_import01.py
  index 95624150c..1bf5838df 100644
  --- a/test/suite/test_import01.py
  +++ b/test/suite/test_import01.py
  @@ -159,6 +159,7 @@ class test_import01(test_import_base):
           for i in range(min_idx, max_idx):
               self.update(self.uri, self.keys[i], self.values[i], self.ts[i])
           self.session.checkpoint()
  +        self.session.checkpoint("name=---")
   
           # Export the metadata for the table.
           c = self.session.open_cursor('metadata:', None, None)

• Other cases include Checkpoint names starting with `(`, `^`, `#`, `%`, `*`, `+`, `=`, `@` and other.
• In some cases we do receive a Parsing Error, but it isn’t consistent across all error-prone inputs

Possible solution:

• Error out when attempting to create a checkpoint with an invalid name.