Ensure @DateTimeFormat tests pass on Java 9+

Prior to this commit, two tests for exception handling regarding
@DateTimeFormat processing only passed on Java 8. This is due to the
fact that the toString() implementation for annotations changed in Java
9. Specifically, the representation for arrays changed from [] to {},
and strings are enclosed in double quotes beginning with Java 9.

This commit ensures that the affected @DateTimeFormat tests pass on
Java 9+, by making the assertions more lenient regarding toString()
output for annotations.

See gh-26777
See gh-26804

spring-context/src/test/java/org/springframework/format/datetime/DateFormattingTests.java

@@ -140,10 +140,14 @@ public class DateFormattingTests {
 					.hasCauseInstanceOf(ParseException.class).getCause()
 						// Unable to parse date time value "99/01/01" using configuration from
 						// @org.springframework.format.annotation.DateTimeFormat(pattern=, style=S-, iso=NONE, fallbackPatterns=[])
+						// We do not check "fallbackPatterns=[]", since the array representation in the toString()
+						// implementation for annotations changed from [] to {} in Java 9. In addition, strings
+						// are enclosed in double quotes beginning with Java 9. Thus, we cannot check directly
+						// for the presence of "style=S-".
 						.hasMessageContainingAll(
 							"Unable to parse date time value \"99/01/01\" using configuration from",
 							"@org.springframework.format.annotation.DateTimeFormat",
-							"style=S-", "iso=NONE", "fallbackPatterns=[]")
+							"style=", "S-", "iso=NONE")
 						.hasCauseInstanceOf(ParseException.class).getCause()
 							.hasMessageStartingWith("Unparseable date: \"99/01/01\"")
 							.hasNoCause();

spring-context/src/test/java/org/springframework/format/datetime/standard/DateTimeFormattingTests.java

@@ -339,10 +339,11 @@ class DateTimeFormattingTests {
 					.hasCauseInstanceOf(DateTimeParseException.class).getCause()
 						// Unable to parse date time value "2009-31-10" using configuration from
 						// @org.springframework.format.annotation.DateTimeFormat(pattern=, style=SS, iso=DATE, fallbackPatterns=[])
+						// We do not check "fallbackPatterns=[]", since the array representation in the toString()
+						// implementation for annotations changed from [] to {} in Java 9.
 						.hasMessageContainingAll(
 							"Unable to parse date time value \"2009-31-10\" using configuration from",
-							"@org.springframework.format.annotation.DateTimeFormat",
-							"iso=DATE", "fallbackPatterns=[]")
+							"@org.springframework.format.annotation.DateTimeFormat", "iso=DATE")
 						.hasCauseInstanceOf(DateTimeParseException.class).getCause()
 							.hasMessageStartingWith("Text '2009-31-10'")
 							.hasCauseInstanceOf(DateTimeException.class).getCause()