Un-modify tupleassign and function2 tests (#3158)

I manually changed these in #3080 and #3083 to get the tests passing (with notes around the deviations) -- but that's no longer necessary, now that we have proper testing that takes deviations into account.

crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/function2.py.expect

@@ -5,8 +5,7 @@ def f(
     with cache_dir():
         if something:
             result = CliRunner().invoke(
-                black.main,
-                [str(src1), str(src2), "--diff", "--check"],
+                black.main, [str(src1), str(src2), "--diff", "--check"]
             )
     limited.append(-limited.pop())  # negate top
     return A(

crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/tupleassign.py.expect

@@ -4,11 +4,7 @@
     sdfjsdfjlksdljkfsdlkf,
     sdfsdjfklsdfjlksdljkf,
     sdsfsdfjskdflsfsdf,
-) = (
-    1,
-    2,
-    3,
-)
+) = (1, 2, 3)
 
 # This is as well.
 (this_will_be_wrapped_in_parens,) = struct.unpack(b"12345678901234567890")