[Wasm] Support Wasm GC milestone 5

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

@@ -1,7 +1,3 @@
-// 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.
 
 open class Foo {
     open fun foo(x: CharSequence = "O"): CharSequence = x

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

@@ -1,7 +1,3 @@
-// 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.
 
 open class Foo {
     open fun foo(x: CharSequence = "O"): CharSequence = x

compiler/testData/codegen/box/inference/coercionToUnitWithLastLambdaExpression.kt

@@ -1,3 +1,4 @@
+// IGNORE_BACKEND: WASM
 
 fun <T> myRun(action: () -> T): T = action()
 fun foo(): String = "foo"

compiler/testData/codegen/boxWasmJsInterop/functionTypes.kt

@@ -1,3 +1,5 @@
+// V8 fail: https://bugs.chromium.org/p/v8/issues/detail?id=12834
+// IGNORE_BACKEND: WASM
 
 // Char issues
 // IGNORE_BACKEND: JS_IR