Merge #12076: qa: Use node.datadir instead of tmpdir in test framework

c8330d4 qa: Use node.datadir instead of tmpdir in test framework (MarcoFalke)

Pull request description:

  Commit c53c9831ee introduced the utility function `get_datadir_path`, however not all places in the code use this util function. Using the util function everywhere makes it easier to review pull requests related to the datadir.

  This commit replaces datadir path creation with the `datadir` member of `TestNode`, which itself uses `get_datadir_path`.

Tree-SHA512: c75707ab7149d732a6d56152a5813138a33459d3d07577b60b89f2a207c83b7663fac5f203593677c9892d1c23a5eba4bd45c5c4ababf040d720b437240fcddf

test/functional/feature_config_args.py

@@ -8,7 +8,7 @@ import os
 import re
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import get_datadir_path
+
 
 class ConfArgsTest(BitcoinTestFramework):
     def set_test_params(self):
@@ -20,7 +20,7 @@ class ConfArgsTest(BitcoinTestFramework):
         # Remove the -datadir argument so it doesn't override the config file
         self.nodes[0].args = [arg for arg in self.nodes[0].args if not arg.startswith("-datadir")]
 
-        default_data_dir = get_datadir_path(self.options.tmpdir, 0)
+        default_data_dir = self.nodes[0].datadir
         new_data_dir = os.path.join(default_data_dir, 'newdatadir')
         new_data_dir_2 = os.path.join(default_data_dir, 'newdatadir2')