Add Date.UTC(+/-Infinity) single arg test variants to infinity-make-day.js

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

test/built-ins/Date/UTC/infinity-make-day.js

@@ -6,7 +6,7 @@ es6id: 20.3.3.4
 description: Infinite values specified to MakeDay produce NaN
 info: |
   [...]
-  9. Return TimeClip(MakeDate(MakeDay(yr, m, dt), MakeTime(h, min, s, milli))). 
+  9. Return TimeClip(MakeDate(MakeDay(yr, m, dt), MakeTime(h, min, s, milli))).
 
   MakeDay (year, month, date)
 
@@ -14,6 +14,9 @@ info: |
      NaN.
 ---*/
 
+assert.sameValue(Date.UTC(Infinity), NaN, 'year: Infinity - single arg');
+assert.sameValue(Date.UTC(-Infinity), NaN, 'year: -Infinity - single arg');
+
 assert.sameValue(Date.UTC(Infinity, 0), NaN, 'year: Infinity');
 assert.sameValue(Date.UTC(-Infinity, 0), NaN, 'year: -Infinity');
 
@@ -22,3 +25,4 @@ assert.sameValue(Date.UTC(0, -Infinity), NaN, 'month: -Infinity');
 
 assert.sameValue(Date.UTC(0, 0, Infinity), NaN, 'date: Infinity');
 assert.sameValue(Date.UTC(0, 0, -Infinity), NaN, 'date: -Infinity');
+