Minor fix to leading dot, reader-based parser

Author: cowtowncoder

src/main/java/com/fasterxml/jackson/core/json/ReaderBasedJsonParser.java

@@ -1600,7 +1600,10 @@ private final JsonToken _parseNumber2(boolean neg, int startPtr) throws IOExcept
         }
         // Also, integer part is not optional
         if (intLen == 0) {
-            return _handleInvalidNumberStart(c, neg);
+            // [core#611]: allow optionally leading decimal point
+            if (!isEnabled(JsonReadFeature.ALLOW_LEADING_DECIMAL_POINT_FOR_NUMBERS.mappedFeature())) {
+                return _handleInvalidNumberStart(c, neg);
+            }
         }
 
         int fractLen = 0;

src/test/java/com/fasterxml/jackson/core/read/NonStandardNumberParsingTest.java

@@ -83,7 +83,7 @@ public void testLeadingDotInDecimalAllowedBytes() throws Exception {
 
     public void testLeadingDotInDecimalAllowedReader() throws Exception {
         _testLeadingDotInDecimalAllowed(jsonFactory(), MODE_READER);
-//        _testLeadingDotInDecimalAllowed(jsonFactory(), MODE_READER_THROTTLED);
+        _testLeadingDotInDecimalAllowed(jsonFactory(), MODE_READER_THROTTLED);
     }
 
     public void testTrailingDotInDecimalAllowedDataInput() throws Exception {