optimization: Don't include ASCII characters in Unicode tables

The ASCII subset of Unicode is fixed and will never change, so we don't
need to generate tables for it with every new Unicode version. This
saves a few bytes of static data and speeds up `char::is_control` and
`char::is_grapheme_extended` on ASCII inputs.

Author: Kmeakin

library/core/src/char/methods.rs

@@ -950,7 +950,7 @@ impl char {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_control(self) -> bool {
-        unicode::Cc(self)
+        if self.is_ascii() { self.is_ascii_control() } else { unicode::Cc(self) }
     }
 
     /// Returns `true` if this `char` has the `Grapheme_Extend` property.
@@ -965,7 +965,7 @@ impl char {
     #[must_use]
     #[inline]
     pub(crate) fn is_grapheme_extended(self) -> bool {
-        unicode::Grapheme_Extend(self)
+        !self.is_ascii() && unicode::Grapheme_Extend(self)
     }
 
     /// Returns `true` if this `char` has one of the general categories for numbers.