[test] Mute failing irText tests

compiler/testData/ir/irText/declarations/contextReceivers/plusMatrix.kt

@@ -1,6 +1,8 @@
 // FIR_IDENTICAL
 // !LANGUAGE: +ContextReceivers
 // !DIAGNOSTICS: -UNUSED_PARAMETER
+// IGNORE_BACKEND_K2: JS_IR
+// IGNORE_BACKEND_K2: JS_IR_ES6
 
 interface NumberOperations {
     fun Number.plus(other: Number): Number
@@ -13,4 +15,4 @@ context(NumberOperations) fun Matrix.plus(other: Matrix): Matrix = TODO()
 fun NumberOperations.plusMatrix(m1: Matrix, m2: Matrix) {
     m1.plus(m2)
     m2.plus(m1)
-}
+}