SR-300: Reenable Timezone abbreviation tests

Author: spevans

TestFoundation/TestTimeZone.swift

@@ -13,8 +13,7 @@ class TestTimeZone: XCTestCase {
 
     static var allTests: [(String, (TestTimeZone) -> () throws -> Void)] {
         return [
-            // Disabled see https://bugs.swift.org/browse/SR-300
-            // ("test_abbreviation", test_abbreviation),
+            ("test_abbreviation", test_abbreviation),
 
             // Disabled because `CFTimeZoneSetAbbreviationDictionary()` attempts
             // to release non-CF objects while removing values from
@@ -26,9 +25,7 @@ class TestTimeZone: XCTestCase {
             ("test_initializingTimeZoneWithOffset", test_initializingTimeZoneWithOffset),
             ("test_initializingTimeZoneWithAbbreviation", test_initializingTimeZoneWithAbbreviation),
             ("test_localizedName", test_localizedName),
-            // Also disabled due to https://bugs.swift.org/browse/SR-300
-            // ("test_systemTimeZoneUsesSystemTime", test_systemTimeZoneUsesSystemTime),
-
+            ("test_systemTimeZoneUsesSystemTime", test_systemTimeZoneUsesSystemTime),
             ("test_customMirror", test_tz_customMirror),
             ("test_knownTimeZones", test_knownTimeZones),
             ("test_systemTimeZoneName", test_systemTimeZoneName),