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

idea/testData/intentions/infixCallToOrdinary/functionLiteralArgument.kt

@@ -1,5 +1,5 @@
 interface Foo {
-    fun foo(f: (Int) -> Unit)
+    infix fun foo(f: (Int) -> Unit)
 }
 fun foo(x: Foo) {
     x <caret>foo { it * 2 }

idea/testData/intentions/infixCallToOrdinary/functionLiteralArgument.kt.after

@@ -1,5 +1,5 @@
 interface Foo {
-    fun foo(f: (Int) -> Unit)
+    infix fun foo(f: (Int) -> Unit)
 }
 fun foo(x: Foo) {
     x.foo { it * 2 }

idea/testData/intentions/infixCallToOrdinary/nullAssertedCall.kt

@@ -1,3 +1,5 @@
+infix fun String.compareTo(other: String) = 0
+
 fun foo(x: String) {
     x!! <caret>compareTo "1"
 }

idea/testData/intentions/infixCallToOrdinary/nullAssertedCall.kt.after

@@ -1,3 +1,5 @@
+infix fun String.compareTo(other: String) = 0
+
 fun foo(x: String) {
     x!!.compareTo("1")
 }

idea/testData/intentions/infixCallToOrdinary/parenthesesAroundRightHandArgument.kt

@@ -1,3 +1,5 @@
+infix fun String.add(other: String) = ""
+
 fun foo(x: String) {
-    x plus<caret> ("1" + "2")
+    x add<caret> ("1" + "2")
 }

idea/testData/intentions/infixCallToOrdinary/parenthesesAroundRightHandArgument.kt.after

@@ -1,3 +1,5 @@
+infix fun String.add(other: String) = ""
+
 fun foo(x: String) {
-    x.plus("1" + "2")
+    x.add("1" + "2")
 }

idea/testData/intentions/infixCallToOrdinary/simpleInfixFunctionCall.kt

@@ -1,3 +1,5 @@
+infix fun Int.compareTo(other: Int) = 0
+
 fun foo(x: Int) {
     x <caret>compareTo 1
 }

idea/testData/intentions/infixCallToOrdinary/simpleInfixFunctionCall.kt.after

@@ -1,3 +1,5 @@
+infix fun Int.compareTo(other: Int) = 0
+
 fun foo(x: Int) {
     x.compareTo(1)
 }