Potential typos in patterns tests

[chloestefantsova]

It looks like it should say negative instead of nagative in the following lines in a test.

co19/LanguageFeatures/Patterns/constant_A02_t03.dart

Lines 62 to 63 in ac4a905

	Negative => "nagative",
	NegativePi => "nagative-pi",

Similarly, it seems that this line in another test should say blue instead of default.

co19/LanguageFeatures/Patterns/constant_A02_t15.dart

Line 52 in ac4a905

Color.blue => "default",