Rename exception variables in empty catch blocks

The Spring codebase sometimes ignores exceptions in catch blocks on
purpose. This is often called out by an inline comment.
We should make this more obvious by renaming the exception argument in
the catch block to declare whether the exception is "ignored" or
"expected".

See gh-35047

Signed-off-by: Vincent Potucek <vpotucek@me.com>
[brian.clozel@broadcom.com: rework commit message]
Signed-off-by: Brian Clozel <brian.clozel@broadcom.com>

spring-context/src/test/java/org/springframework/aop/framework/AbstractAopProxyTests.java

@@ -233,8 +233,7 @@ abstract class AbstractAopProxyTests {
 		try {
 			p2.echo(new IOException());
 		}
-		catch (IOException ex) {
-
+		catch (IOException ignored) {
 		}
 		assertThat(cta.getCalls()).isEqualTo(2);
 	}