Test for \s matching CRLF when scalar matching (#648)

Author: natecook1000

Tests/RegexTests/UTS18Tests.swift

@@ -286,6 +286,9 @@ extension UTS18Tests {
     // Test \v - vertical space
     lines = lineInput.matches(of: regex(#"\d{2}\v^"#).anchorsMatchLineEndings())
     XCTAssertEqual(lines.count, 11)
+    // Test \s - whitespace
+    lines = lineInput.matches(of: regex(#"\d{2}\s^"#).anchorsMatchLineEndings())
+    XCTAssertEqual(lines.count, 11)
     // Test anchors as line boundaries
     lines = lineInput.matches(of: regex(#"^\d{2}$"#).anchorsMatchLineEndings())
     XCTAssertEqual(lines.count, 12)
@@ -301,6 +304,10 @@ extension UTS18Tests {
     lines = lineInput.matches(
       of: regex(#"\d{2}\v(?=\d)"#).matchingSemantics(.unicodeScalar).anchorsMatchLineEndings())
     XCTAssertEqual(lines.count, 10)
+    // Unicode scalar semantics - \s matches all except for \r\n sequence
+    lines = lineInput.matches(
+      of: regex(#"\d{2}\s(?=\d)"#).matchingSemantics(.unicodeScalar).anchorsMatchLineEndings())
+    XCTAssertEqual(lines.count, 10)
 
     // Does not contain an empty line
     XCTAssertFalse(lineInput.contains(regex(#"^$"#)))