Fix CharInClass reference in regex emitter (#61559)

We've tried to consistently use global:: whenever referring to core library types in the regex generator emitted code.  I'd missed these two.

(That said, these make the code a lot harder to read, especially in places where we're unable to use extension methods as extensions, so we'll want to revisit this policy.)

Author: stephentoub

src/libraries/System.Text.RegularExpressions/gen/RegexGenerator.Emitter.cs

@@ -3419,8 +3419,8 @@ private static string MatchCharacterClass(bool hasTextInfo, RegexOptions options
             // characters other than that some might be included, for example if the character class
             // were [\w\d], so since ch >= 128, we need to fall back to calling CharInClass.
             return invariant ?
-                $"((ch = {chExpr}) < 128 ? ({Literal(bitVectorString)}[ch >> 4] & (1 << (ch & 0xF))) != 0 : CharInClass(char.ToLowerInvariant((char)ch), {Literal(charClass)}))" :
-                $"((ch = {chExpr}) < 128 ? ({Literal(bitVectorString)}[ch >> 4] & (1 << (ch & 0xF))) != 0 : CharInClass((char)ch, {Literal(charClass)}))";
+                $"((ch = {chExpr}) < 128 ? ({Literal(bitVectorString)}[ch >> 4] & (1 << (ch & 0xF))) != 0 : global::System.Text.RegularExpressions.RegexRunner.CharInClass(char.ToLowerInvariant((char)ch), {Literal(charClass)}))" :
+                $"((ch = {chExpr}) < 128 ? ({Literal(bitVectorString)}[ch >> 4] & (1 << (ch & 0xF))) != 0 : global::System.Text.RegularExpressions.RegexRunner.CharInClass((char)ch, {Literal(charClass)}))";
         }
 
         private static string Literal(char c) => SymbolDisplay.FormatLiteral(c, quote: true);