Accept reversed dataclass field-order warning

Extend PyTypingConformanceTest to allow the alternative diagnostic
emitted when a dataclass field with a default precedes a field
without a default.

Both messages represent the same semantic error but differ in
field-order phrasing.

Author: azimsh3r

conformance/tests/dataclasses_usage.py

@@ -57,19 +57,19 @@ def __call__(
 # > single class, or as a result of class inheritance.
 @dataclass  # E[DC1]
 class DC1:
-    a: int = 0
+    a: int = 0 # E[DC1]: field with default should follow a field with no default.
     b: int  # E[DC1]: field with no default cannot follow field with default.
 
 
 @dataclass  # E[DC2]
 class DC2:
-    a: int = field(default=1)
+    a: int = field(default=1) # E[DC2]: field with default should follow a field with no default.
     b: int  # E[DC2]: field with no default cannot follow field with default.
 
 
 @dataclass  # E[DC3]
 class DC3:
-    a: InitVar[int] = 0
+    a: InitVar[int] = 0 # E[DC3]: field with default should follow a field with no default.
     b: int  # E[DC3]: field with no default cannot follow field with default.