FIR IDE: run FIR highlighting test on all test data

Similarly to FIR diagnostic tests. This commit enable all available test
data and check the reported error messages by FIR. This helps identify
some issues in formatting of FIR diagnostics.

The changes on the test file are mechanically generated. Failed tests
are disabled with `// IGNORE_FIR` and are re-enabled in the second
commit.

idea/testData/checker/ExtensionFunctions.fir.kt

@@ -0,0 +1,70 @@
+fun Int?.optint() : Unit {}
+val Int?.optval : Unit get() = Unit
+
+fun <T: Any, E> T.foo(x : E, y : A) : T   {
+  y.plus(1)
+  y plus 1
+  y + 1.0
+
+  this?.minus<T>(this)
+
+  return this
+}
+
+class A
+
+infix operator fun A.plus(a : Any) {
+
+  1.foo()
+  true.<error descr="[INAPPLICABLE_CANDIDATE] Inapplicable candidate(s): /foo">foo</error>()
+
+  1
+}
+
+infix operator fun A.plus(a : Int) {
+  1
+}
+
+fun <T> T.minus(t : T) : Int = 1
+
+fun test() {
+  val y = 1.abs
+}
+val Int.abs : Int
+  get() = if (this > 0) this else -this;
+
+<error descr="[EXTENSION_PROPERTY_MUST_HAVE_ACCESSORS_OR_BE_ABSTRACT] Extension property must have accessors or be abstract">val <T> T.foo : T</error>
+
+fun Int.foo() = this
+
+// FILE: b.kt
+//package null_safety
+
+        fun parse(cmd: String): Command? { return null  }
+        class Command() {
+        //  fun equals(other : Any?) : Boolean
+          val foo : Int = 0
+        }
+
+        operator fun Any.equals(other : Any?) : Boolean = true
+        fun Any?.equals1(other : Any?) : Boolean = true
+        fun Any.equals2(other : Any?) : Boolean = true
+
+        fun main(args: Array<String>) {
+
+            System.out.print(1)
+
+            val command = parse("")
+
+            command.foo
+
+            command<error descr="[UNSAFE_CALL] Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type Command?">.</error>equals(null)
+            command?.equals(null)
+            command.equals1(null)
+            command?.equals1(null)
+
+            val c = Command()
+            c?.equals2(null)
+
+            if (command == null) 1
+        }