scripts: Switched to tomllib/tomli for toml parsing

Found a bug in our toml parser that's difficult to work around:

  defines.GC_FLAGS = """      =>  {
      LFS_GC_MKCONSISTENT             "GC_FLAGS": "blablabla",
          | LFS_GC_LOOKAHEAD      }   // where did defines go?
  """

This appears to be this bug:

https://github.com/uiri/toml/issues/286

But since it was opened 4 years ago, I think it's safe to say this toml
library is now defunct...

---

Apparently tomllib/tomli is the new hotness, which started as tomli
before being adopt in Python 3.11 as tomllib. Fortunately tomli is still
maintained so we don't have to worry about Python versions too much.

Adopting tomli was relatively straightforward, the only hiccup being
that it doesn't support text files? Curious, but fortunately Python
exposes the underlying binary file handle in f.buffer.

scripts/test.py

@@ -30,7 +30,11 @@ import subprocess as sp
 import sys
 import threading as th
 import time
-import toml
+
+try:
+    import tomllib as toml
+except ModuleNotFoundError:
+    import tomli as toml
 
 
 RUNNER_PATH = ['./runners/test_runner']
@@ -188,7 +192,7 @@ class TestSuite:
         # load toml file and parse test cases
         with open(self.path) as f:
             # load tests
-            config = toml.load(f)
+            config = toml.load(f.buffer)
 
             # find line numbers
             f.seek(0)