pitest: increase mutation coverage for pitest-checkstyle-tree-walker profile to 100%

[Nimfadora]

We created pitest profiles for non-checks code in #4367. Currently, we should increase coverage for pitest-checkstyle-tree-walker profile up to 100%.
This issue is a subtask of #3708

Current threshold of pitest-checkstyle-tree-walker profile: 83

[romani]

@Nimfadora ,

TreeWalker.java//lexer.setFilename(contents.getFileName());

lexer/parser is using getFilename when error in parsing is happening, try to feed parser with bad source file from lexer and syntax perspective to cover both cases.

TreeWalker.java//lexer.setTreatAssertAsKeyword(true);
lexer.setTreatEnumAsKeyword(true);

looks like you need to feed a java file with "enum" and "assert" , as I see from his code Lexer do special processing of them in its code.

ordinaryChecksResources.size() + commentChecksResources.size()

try to move them inside Hashset c-tor, if still a problem, remove this line completely.

isPositionGreater

it might be related to cases where you put /**/ at all places in class , instead of all space.
Try to change in big input file all spaces to /**/ and see a coverage. If covered, minimize input file and ... . If not covered , add to suppress.

countLinesColumns

related to javadoc Checks, you need to run javadoc Checks that are based on AbstractJavadocCheck to see effect.

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JavadocDetailNodeParser.java

parseJavadocAsParseTree

run javadoc files with syntax/parsing problems.

node.setChildren((DetailNode[]) new JavadocNodeImpl[parseTree.getChildCount()]);

run all javadoc Check that are based AbstractJavadocCheck to see what input file is required.

getNextSibling

run all javadoc Check that are based AbstractJavadocCheck to see what input file is required.
If no luck, suppress pitest on this method for now.

[romani]

profile is set to 100%, but issue is not done yet as there a lot of excludedMethods .

[romani]

Final fix is merged