IDEA plugin: fixed crashing ifExpressionToElvis intention when applying to if expression which is part of another expression.

#EA-57307 fixed

idea/testData/intentions/branched/ifThenToElvis/ifAsPartOfExpression.kt

@@ -0,0 +1,9 @@
+fun maybeFoo(): String? {
+    return "foo"
+}
+
+fun main(args: Array<String>) {
+    val foo = maybeFoo()
+    val bar = "bar"
+    val x = "baz" + if (foo == null<caret>) bar else foo
+}

idea/testData/intentions/branched/ifThenToElvis/ifAsPartOfExpression.kt.after

@@ -0,0 +1,8 @@
+fun maybeFoo(): String? {
+    return "foo"
+}
+
+fun main(args: Array<String>) {
+    val bar = "bar"
+    val x = "baz" + (maybeFoo() ?: bar)
+}

idea/testData/intentions/branched/ifThenToElvis/inspectionData/expected.xml

@@ -47,6 +47,14 @@
     <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?:'.</problem_class>
     <description>Replace 'if' expression with elvis expression</description>
   </problem>
+  <problem>
+    <file>ifAsPartOfExpression.kt</file>
+    <line>8</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/src/ifAsPartOfExpression.kt" />
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?:'.</problem_class>
+    <description>Replace 'if' expression with elvis expression</description>
+  </problem>
   <problem>
     <file>ifAndElseNotInBlocks.kt</file>
     <line>8</line>