SQL: [Tests] Mute testReplaceChildren for Pivot

[matriv]

Temporarily "mute" the testReplaceChildren for Pivot since it leads to
failing tests for some seeds, since the new child doesn't respond to a
valid data type.

Relates to #48900

[elasticmachine]

Pinging @elastic/es-search (:Search/SQL)

[astefan]

I believe a cleaner approach would be the use of JUnit's Assume class. One example is https://github.com/elastic/elasticsearch/blob/master/x-pack/plugin/sql/qa/src/main/java/org/elasticsearch/xpack/sql/qa/jdbc/SqlSpecTestCase.java#L78-L84.

[matriv]

I believe a cleaner approach would be the use of JUnit's Assume class. One example is https://github.com/elastic/elasticsearch/blob/master/x-pack/plugin/sql/qa/src/main/java/org/elasticsearch/xpack/sql/qa/jdbc/SqlSpecTestCase.java#L78-L84.

I'm sorry I don't get how it can improve it, this method is run with every class extending Node as a subclass.

[matriv]

Closing in favour of a proper fix: #49004

[astefan]

Instead of using the return when that condition was met, an Assume.assumeFalse(subclass.equals(Pivot.class)) would have been enough. It wasn't about the class checking itself, but about the test's assumption that a certain condition should be met through the use of Assume.