Fix number parsing to not allow space between sign and digits.

src/conversions.cc

Index: src/conversions.cc
diff --git a/src/conversions.cc b/src/conversions.cc
index 19fa7773abf6edfedf9c54e9dfdea4674d3919bd..a954d6cc694748e2629451fe816d400ac9c6459d 100644
--- a/src/conversions.cc
+++ b/src/conversions.cc
@@ -448,12 +448,12 @@ static double InternalStringToDouble(Iterator current,
   bool sign = false;
 
   if (*current == '+') {
-    // Ignore leading sign; skip following spaces.
+    // Ignore leading sign.
     ++current;
-    if (!AdvanceToNonspace(&current, end)) return JUNK_STRING_VALUE;
+    if (current == end) return JUNK_STRING_VALUE;
   } else if (*current == '-') {
     ++current;
-    if (!AdvanceToNonspace(&current, end)) return JUNK_STRING_VALUE;
+    if (current == end) return JUNK_STRING_VALUE;
     sign = true;
   }