Fix tests: "infix modifier required" and "operator modifier required" errors

idea/testData/unifier/equivalence/declarations/localCallables/multiDeclaration.kt

@@ -7,7 +7,7 @@ fun foo1() {
 }
 
 fun foo2() {
-    fun A.component1(): Int = a + 1
+    operator fun A.component1(): Int = a + 1
 
     val (aa, bb) = A(1, "2")
     val (uu, vv) = A(2, "2")

idea/testData/unifier/equivalence/expressions/calls/externalArgumentsRuntime.kt

@@ -1,4 +1,4 @@
-fun Int.contains(n: Int): Boolean = n < this
+operator fun Int.contains(n: Int): Boolean = n < this
 
 fun foo(n: Int): Int {
     if (n in 1) {

idea/testData/unifier/equivalence/expressions/conventions/inc.kt

@@ -1,4 +1,4 @@
-fun String.inc() = this + "+"
+operator fun String.inc() = this + "+"
 
 class Foo {
     init {

idea/testData/unifier/equivalence/expressions/conventions/infixCall.kt

@@ -1,3 +1 @@
-val a = <selection>1 + 2</selection>
-val b = 1 plus 2
-val d = 2 plus 1
+val a = <selection>1 + 2</selection>

idea/testData/unifier/equivalence/expressions/conventions/infixCall.kt.match

@@ -1,3 +1 @@
-1 + 2
-
-1 plus 2
+1 + 2