[Wasm] Update testData after adding K2 and new test infra support.

- Actualize muted K2 tests
- Actualize muted K1 tests with module systems because legacy Wasm test
  infra had no respect for "// MODULE: ..." test directives

compiler/testData/codegen/box/strings/constInStringTemplate.kt

@@ -1,5 +1,5 @@
-// IGNORE_BACKEND: WASM
-// WASM_MUTE_REASON: Float.toString()
+// IGNORE_BACKEND_K1: WASM
+// IGNORE_BACKEND_K2: WASM
 // WITH_STDLIB
 
 import kotlin.test.assertEquals