FoundationEssentialsTests: skip distant{Future,Past} tests on Windows

The MSVC libc does not properly handle dates that are far out from the
Unix epoch. For the purposes of allowing the test suite to pass on CI,
skip these tests on Windows.

Author: compnerd

Tests/FoundationEssentialsTests/DateTests.swift

@@ -18,6 +18,14 @@ import TestSupport
 @testable import FoundationEssentials
 #endif
 
+private func libcIsUCRT() -> Bool {
+    #if os(Windows)
+    return true
+    #else
+    return false
+    #endif
+}
+
 final class DateTests : XCTestCase {
 
     func testDateComparison() {
@@ -90,15 +98,18 @@ final class DateTests : XCTestCase {
         XCTAssertEqual("1970-01-01 00:00:00 +0000", date.description)
     }
 
-    func testDescriptionDistantPast() {
+    func testDescriptionDistantPast() throws {
+        try XCTSkipIf(libcIsUCRT(), "ucrt does not support distant past")
+
 #if FOUNDATION_FRAMEWORK
         XCTAssertEqual("0001-01-01 00:00:00 +0000", Date.distantPast.description)
 #else
         XCTAssertEqual("0000-12-30 00:00:00 +0000", Date.distantPast.description)
 #endif
     }
 
-    func testDescriptionDistantFuture() {
+    func testDescriptionDistantFuture() throws {
+        try XCTSkipIf(libcIsUCRT(), "ucrt does not support distant future")
         XCTAssertEqual("4001-01-01 00:00:00 +0000", Date.distantFuture.description)
     }