markused,builtin,strconv,vlib: reduce generated C sizes for compilers != tcc, for short programs, by simplifying the generation of backtraces, and reducing string interpolations in panics (#23380)

vlib/x/json2/decoder2/decode.v

@@ -1124,6 +1124,6 @@ pub fn string_buffer_to_generic_number[T](result &T, data []u8) {
 		}
 		*result = T(enumeration)
 	} $else {
-		panic('unsupported type ${typeof[T]().name}')
+		panic('unsupported type ' + typeof[T]().name)
 	}
 }