Effects: add diagnostic tests on functions from stdlib

==========
Introduction of EffectSystem: 18/18

compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/fromStandardKt.kt

@@ -0,0 +1,110 @@
+// !LANGUAGE: +CallsInPlaceEffect
+// !DIAGNOSTICS: -INVISIBLE_REFERENCE -INVISIBLE_MEMBER
+
+fun testRunWithUnitReturn() {
+    val x: Int
+    run { x  = 42 }
+    println(x)
+}
+
+fun testRunWithReturnValue() {
+    val x: Int
+    val y = run {
+        x = 42
+        "hello"
+    }
+    println(x)
+    println(y)
+}
+
+fun testRunWithCoercionToUnit() {
+    val <!ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE!>x<!>: Int
+    run {
+        x = 42
+        "hello"
+    }
+}
+
+fun testRunWithReceiver(x: Int) {
+    val s: String
+    x.run {
+        s = this.toString()
+    }
+    println(s)
+}
+
+fun testWith(x: Int) {
+    val s: String
+    with(x) {
+        s = toString()
+    }
+    println(s)
+}
+
+fun testApply(x: Int) {
+    val y: Int
+    val z: Int = x.apply { y = 42 }
+    println(y)
+    println(z)
+}
+
+fun testAlso(x: Int) {
+    val y: Int
+    x.also { y = it + 1 }
+    println(y)
+}
+
+fun testLet(x: Int) {
+    val z: Int
+    val y: String = x.let {
+        z = 42
+        (it + 1).toString()
+    }
+    println(z)
+    println(y)
+}
+
+fun testTakeIf(x: Int?) {
+    val y: Int
+    x.takeIf {
+        y = 42
+        it != null
+    }
+    println(y)
+}
+
+fun testTakeUnless(x: Int?) {
+    val y: Int
+    x.takeIf {
+        y = 42
+        it != null
+    }
+    println(y)
+}
+
+fun testRepeatOnVal(x: Int) {
+    val y: Int
+    repeat(x) {
+        // reassignment instead of captured val initalization
+        <!VAL_REASSIGNMENT!>y<!> = 42
+    }
+    println(<!UNINITIALIZED_VARIABLE!>y<!>)
+}
+
+fun testRepeatOnVar(x: Int) {
+    var y: Int
+    repeat(x) {
+        // no reassignment reported
+        y = 42
+    }
+    // but here we still unsure if 'y' was initialized
+    println(<!UNINITIALIZED_VARIABLE!>y<!>)
+}
+
+fun testRepeatOnInitializedVar(x: Int) {
+    var y: Int = 24
+    repeat(x) {
+        y = 42
+    }
+    println(y)
+}