K2: Update extension receiver after checking in CheckExtensionReceiver

fixes receiver selection when the candidate has more that one possible
extension receiver
#KT-62129 fixed

compiler/testData/codegen/box/extensionFunctions/contextReceivers/withTwoContextReceivers.kt

@@ -0,0 +1,12 @@
+// !LANGUAGE: +ContextReceivers
+// TARGET_BACKEND: JVM_IR
+
+class A { val o = "O" }
+class B { val k = "K" }
+
+val A.bar get() = o
+
+context(A, B)
+fun ok() = bar + k
+
+fun box(): String = with(A()) { with(B()) { ok() } }