Refresh test results, and remove test case that depended on C++23

Right now the regression tests target the minimum supported compilers, so there's no easy way to write regression tests that depend on post-C++20 features... that's something that can be added in the future, perhaps with `-latest` or similar tags in the test names

Author: hsutter

regression-tests/pure2-bugfix-for-empty-index.cpp2

@@ -0,0 +1 @@
+pure2-bugfix-for-variable-template.cpp

regression-tests/test-results/gcc-13/pure2-bugfix-for-empty-index.cpp.output renamed to regression-tests/test-results/clang-12/pure2-bugfix-for-variable-template.cpp.execution

@@ -1,5 +1,5 @@
 
-cppfront compiler v0.2.1   Build 8723:1124
+cppfront compiler v0.2.1   Build 8724:0846
 Copyright(c) Herb Sutter   All rights reserved
 
 SPDX-License-Identifier: CC-BY-NC-ND-4.0

regression-tests/test-results/clang-12/pure2-bugfix-for-variable-template.cpp.output

@@ -1 +1 @@
-"8723:1124"
+"8724:0846"

regression-tests/test-results/msvc-2022/pure2-bugfix-for-variable-template.cpp.execution

@@ -4128,14 +4128,14 @@ class parser
             {
                 auto op  = curr().to_string(true);
                 auto msg = "postfix unary " + op;
-                if      (curr().type() == lexeme::Multiply ) { msg += " (dereference)"         ; }
-                else if (curr().type() == lexeme::Ampersand) { msg += " (address-of)"          ; }
-                else if (curr().type() == lexeme::Tilde    ) { msg += " (unary bit-complement)"; }
+                if      (curr().type() == lexeme::Multiply ) { msg += " (dereference)"          ; }
+                else if (curr().type() == lexeme::Ampersand) { msg += " (address-of)"           ; }
+                else if (curr().type() == lexeme::Tilde    ) { msg += " (unary bit-complement)" ; }
                 msg += " cannot be immediately followed by a (, identifier, or literal - add whitespace before "
                     + op + " here if you meant binary " + op;
-                if      (curr().type() == lexeme::Multiply ) { msg += " (multiplication)"      ; }
-                else if (curr().type() == lexeme::Ampersand) { msg += " (bitwise and)"         ; }
-                else if (curr().type() == lexeme::Tilde    ) { msg += " (binarybit-complement)"; }
+                if      (curr().type() == lexeme::Multiply ) { msg += " (multiplication)"       ; }
+                else if (curr().type() == lexeme::Ampersand) { msg += " (bitwise and)"          ; }
+                else if (curr().type() == lexeme::Tilde    ) { msg += " (binary bit-complement)"; }
 
                 error(msg, false);
                 break;