Implement recovery for incomplete expression before declaration

It's needed when declarations are parsed as a part of previous expression
(see tests)

Currently we apply this kind of recovery in a conservative way,
only when declaration starts at the next line, and while
the condition could be relaxed, there's no need to do this

 #KT-4948 Fixed
 #KT-7118 Fixed

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/declarationAfterDotSelectorExpected.kt

@@ -0,0 +1,29 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+fun foo(x: Any) {
+    x.<!SYNTAX!><!>
+    val foo = 1
+
+    x.<!SYNTAX!><!>
+    fun bar() = 2
+
+    x.
+    <!ILLEGAL_SELECTOR!>fun String.() = 3<!>
+
+    var a = 24.<!SYNTAX!><!>
+    var b = 42.0
+}
+
+class A {
+    val z = "a".<!SYNTAX!><!>
+    val x = 4
+
+    val y = "b".<!SYNTAX!><!>
+    fun baz() = 5
+
+    val q = "c".
+    <!ILLEGAL_SELECTOR!>fun String.() = 6<!>
+
+    var a = 24.<!SYNTAX!><!>
+    var b = 42.0
+}

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/declarationAfterDotSelectorExpected.txt

@@ -0,0 +1,18 @@
+package
+
+public fun foo(/*0*/ x: kotlin.Any): kotlin.Unit
+
+public final class A {
+    public constructor A()
+    public final var a: [ERROR : Type for 24.]
+    public final var b: kotlin.Double
+    public final val q: [ERROR : Type for "c".
+    fun String.() = 6]
+    public final val x: kotlin.Int = 4
+    public final val y: [ERROR : Type for "b".]
+    public final val z: [ERROR : Type for "a".]
+    public final fun baz(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/declarationAfterIncompleteElvis.kt

@@ -0,0 +1,22 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+fun foo(x: Any?) {
+    x ?:<!SYNTAX!><!>
+    val foo = 1
+
+    x ?:<!SYNTAX!><!>
+    fun bar() = 2
+
+    val res: String.() -> Int = null ?:
+    fun String.() = 3
+}
+
+class A {
+    val z = null ?:<!SYNTAX!><!>
+    val x = 4
+
+    val y = null ?:<!SYNTAX!><!>
+    fun baz() = 5
+
+    val q = null ?:
+    fun String.() = 6
+}

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/declarationAfterIncompleteElvis.txt

@@ -0,0 +1,15 @@
+package
+
+public fun foo(/*0*/ x: kotlin.Any?): kotlin.Unit
+
+public final class A {
+    public constructor A()
+    public final val q: kotlin.String.() -> kotlin.Int
+    public final val x: kotlin.Int = 4
+    public final val y: [ERROR : Type for null ?:]
+    public final val z: [ERROR : Type for null ?:]
+    public final fun baz(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}