Do not add the current directory to sys.path any longer

Adding the current directory to `sys.path` can also mean that we're
going to load modules having the same name as stdlib modules or
astroid modules, which can break pylint.
We were doing this since 4becf6f,
but there was indication on why we were doing that.

pylint/lint.py

@@ -1475,11 +1475,15 @@ def fix_import_path(args):
     """
     orig = list(sys.path)
     changes = []
+    seen = set()
+    cwd = os.getcwd()
     for arg in args:
         path = _get_python_path(arg)
-        if path not in changes:
+        if path not in seen and path != cwd:
             changes.append(path)
-    sys.path[:] = changes + ["."] + sys.path
+            seen.add(path)
+
+    sys.path[:] = changes + sys.path
     try:
         yield
     finally:

tests/unittest_lint.py

@@ -165,7 +165,7 @@ def fake_path():
 
 def test_no_args(fake_path):
     with lint.fix_import_path([]):
-        assert sys.path == ["."] + fake_path
+        assert sys.path == fake_path
     assert sys.path == fake_path
 
 
@@ -175,7 +175,7 @@ def test_no_args(fake_path):
 def test_one_arg(fake_path, case):
     with tempdir() as chroot:
         create_files(["a/b/__init__.py"])
-        expected = [join(chroot, "a")] + ["."] + fake_path
+        expected = [join(chroot, "a")] + fake_path
 
         assert sys.path == fake_path
         with lint.fix_import_path(case):
@@ -195,7 +195,7 @@ def test_one_arg(fake_path, case):
 def test_two_similar_args(fake_path, case):
     with tempdir() as chroot:
         create_files(["a/b/__init__.py", "a/c/__init__.py"])
-        expected = [join(chroot, "a")] + ["."] + fake_path
+        expected = [join(chroot, "a")] + fake_path
 
         assert sys.path == fake_path
         with lint.fix_import_path(case):
@@ -214,14 +214,10 @@ def test_two_similar_args(fake_path, case):
 def test_more_args(fake_path, case):
     with tempdir() as chroot:
         create_files(["a/b/c/__init__.py", "a/d/__init__.py", "a/e/f.py"])
-        expected = (
-            [
-                join(chroot, suffix)
-                for suffix in [sep.join(("a", "b")), "a", sep.join(("a", "e"))]
-            ]
-            + ["."]
-            + fake_path
-        )
+        expected = [
+            join(chroot, suffix)
+            for suffix in [sep.join(("a", "b")), "a", sep.join(("a", "e"))]
+        ] + fake_path
 
         assert sys.path == fake_path
         with lint.fix_import_path(case):