[FE] Add context receivers to scope

compiler/testData/diagnostics/tests/extensions/contextReceiver.fir.kt

@@ -0,0 +1,18 @@
+class A {
+    fun h1() {}
+}
+
+class B {
+    fun h2() {}
+}
+
+fun B.foo() {
+    <!UNRESOLVED_REFERENCE!>h1<!>()
+    h2()
+}
+
+context(A)
+fun B.bar() {
+    <!UNRESOLVED_REFERENCE!>h1<!>()
+    h2()
+}

compiler/testData/diagnostics/tests/extensions/contextReceiver.kt

@@ -0,0 +1,18 @@
+class A {
+    fun h1() {}
+}
+
+class B {
+    fun h2() {}
+}
+
+fun B.foo() {
+    <!UNRESOLVED_REFERENCE!>h1<!>()
+    h2()
+}
+
+context(A)
+fun B.bar() {
+    h1()
+    h2()
+}

compiler/testData/diagnostics/tests/extensions/contextReceiver.txt

@@ -0,0 +1,20 @@
+package
+
+public fun B.bar(): kotlin.Unit
+public fun B.foo(): kotlin.Unit
+
+public final class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun h1(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class B {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun h2(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}