[Wasm] DONT_TARGET_WASM_BACKEND => IGNORE_BACKEND in testdata

compiler/testData/codegen/box/defaultArguments/function/covariantOverride.kt

@@ -1,4 +1,4 @@
-// DONT_TARGET_EXACT_BACKEND: WASM
+// IGNORE_BACKEND: WASM
 // WASM_MUTE_REASON: FAKE_OVERRIDE_ISSUES
 // On wasm this will produce conflicting return types, foo will return Any but we will try to interpret it as String.
 // Before wasm native strings this worked by chance because we added unbox intrinsic for strings.

compiler/testData/codegen/box/defaultArguments/function/covariantOverrideGeneric.kt

@@ -1,4 +1,4 @@
-// DONT_TARGET_EXACT_BACKEND: WASM
+// IGNORE_BACKEND: WASM
 // WASM_MUTE_REASON: FAKE_OVERRIDE_ISSUES
 // On wasm this will produce conflicting return types, foo will return Any but we will try to interpret it as String.
 // Before wasm native strings this worked by chance because we added unbox intrinsic for strings.

compiler/testData/codegen/box/defaultArguments/function/funInTraitChain.kt

@@ -1,4 +1,4 @@
-// DONT_TARGET_EXACT_BACKEND: WASM
+// IGNORE_BACKEND: WASM
 // WASM_MUTE_REASON: BRIDGE_ISSUES
 interface Foo {
     fun foo(a: Double = 1.0): Double