Expect a joined detail message in commentAfterOpeningDelimiter-assert

The case came with #175 and ends in the detail message "x below " +
"y": two string literals on one line with no comment between them.
#176 joins such literals, so the formatter now writes "x below y", and
since both were merged every build job of 21.X.X fails on that line.
Each had passed on its own, because #176 was tested without the case.

The expected output now has the joined literal, as #176 did for the
cases of NON-NLS and palantir-10; the input keeps the two literals.

Tests on JDK 21: FormatterCasesTest 915 cases, 1482 tests in all
modules, none failing.

Author: abashev

open-java-format/src/test/resources/test-cases/commentAfterOpeningDelimiter-assert.case

@@ -30,6 +30,6 @@ class T {
         assert
                 /* why */
                 x < y
-                : "x below " + "y";
+                : "x below y";
     }
 }