[IR] Align captured receiver variable naming with old BE

compiler/testData/debug/localVariables/lambdaWithExtensionReceiver.kt

@@ -0,0 +1,19 @@
+
+// FILE: test.kt
+fun foo(block: Long.() -> String): String {
+    return 1L.block()
+}
+
+fun box() {
+    foo {
+        "OK"
+    }
+}
+
+// LOCAL VARIABLES
+// test.kt:8 box:
+// test.kt:4 foo: block:kotlin.jvm.functions.Function1=TestKt$box$1
+// test.kt:9 invoke: $this$foo:long=1:long
+// test.kt:4 foo: block:kotlin.jvm.functions.Function1=TestKt$box$1
+// test.kt:8 box:
+// test.kt:11 box: