CI Fix tests (#1250)

* CI Fix a C++23 template specialization issue

* CI Work around requires support issue in GCC 10

* CI Add explanatory comments to type safety tests

* CI Remove unused file

Author: jarzec

regression-tests/mixed-type-safety-1.cpp2

@@ -14,12 +14,14 @@ print: <T : type> ( msg: std::string, x: T ) =
 
 main: () -> int = 
 {
-    print( "1.1 is int?", 1.1 is int );
-    print( "1   is int?", 1   is int );
+    // Full qualification is necessary to avoid ambiguity in C++23
+    // C++23 defines std::print, which would be picked up here by ADL
+    ::print( "1.1 is int?", 1.1 is int );
+    ::print( "1   is int?", 1   is int );
 
     c := new<Circle>();     // safe by construction
     s : * Shape = c.get();  // safe by Lifetime
-    print("\ns* is Shape? ", s* is Shape  );
-    print(  "s* is Circle?", s* is Circle );
-    print(  "s* is Square?", s* is Square );
+    ::print("\ns* is Shape? ", s* is Shape  );
+    ::print(  "s* is Circle?", s* is Circle );
+    ::print(  "s* is Square?", s* is Square );
 }

regression-tests/pure2-type-safety-1.cpp2

@@ -23,7 +23,9 @@ main: () -> int =
 
 test_generic: ( x, msg ) = {
     msgx: std::string = msg;
-    print( msgx + " is int? ", x is int );
+    // Full qualification is necessary to avoid ambiguity in C++23
+    // C++23 defines std::print, which would be picked up here by ADL
+    ::print( msgx + " is int? ", x is int );
 }
 
 print: ( msg: std::string, b: bool ) = {