LogicConditionNeedOptimizationCheck: false positive on conditions with assignments

[rnveach]

Identified at #678 (comment) ,

$ cat TestClass.java
public class TestClass {
    private int field = 1;

    void method() {
TestClass s = new TestClass(), t = null, u = null;

        // original
        if (((t = s).test()) &&
            ((u = t).field == 1) != null &&
            (u.field) != 2) {}
        // bad fix
        if (((u = t).field == 1) != null &&
            (u.field) != 2 &&
            ((t = s).test())) {}
    }

    public boolean test() { return true; }
}

$ cat TestConfig.xml
<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
          "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">

<module name="Checker">
    <property name="charset" value="UTF-8"/>

    <module name="TreeWalker">
<module name="com.github.sevntu.checkstyle.checks.coding.LogicConditionNeedOptimizationCheck" />
    </module>
</module>

$ java -jar checkstyle-8.9-sevntu-1.29.0-all.jar -c TestConfig.xml TestClass.java
Starting audit...
[ERROR] TestClass.java:8: Condition with && at line 8 position 29 need optimization. All method calls are advised to move to end of logic expression. [LogicConditionNeedOptimization]
[ERROR] TestClass.java:9: Condition with && at line 9 position 41 need optimization. All method calls are advised to move to end of logic expression. [LogicConditionNeedOptimization]
Audit done.
Checkstyle ends with 2 errors.

Re-arranging any of the conditions will cause an NPE. In other circumstances it could cause unwanted behavior from using old values from previous iteration, like the instanceof example.