Kotlin: Add FP test case for unnecessarily complex bool expression

Author: tamasvajk

java/ql/test/kotlin/query-tests/SimplifyBoolExpr/SimplifyBoolExpr.expected

@@ -0,0 +1 @@
+| SimplifyBoolExpr.kt:8:8:8:16 | ... (value equals) ... | Expressions of the form "A == true" can be simplified to "A". |

java/ql/test/kotlin/query-tests/SimplifyBoolExpr/SimplifyBoolExpr.kt

@@ -0,0 +1,13 @@
+fun main() {
+    f(null)
+    f(true)
+    f(false)
+}
+
+fun f(x: Boolean?) {
+    if(x == true) {
+        println("Yes")
+    } else {
+        println("No")
+    }
+}

java/ql/test/kotlin/query-tests/SimplifyBoolExpr/SimplifyBoolExpr.qlref

@@ -0,0 +1 @@
+Violations of Best Practice/Boolean Logic/SimplifyBoolExpr.ql