[FIR] Add inline checker for bodies of inline functions

This checker doesn't support `@PublishedAPI` yet, so some BB tests for it
 were muted. #KT-46270

compiler/testData/codegen/box/publishedApi/simple.kt

@@ -1,3 +1,4 @@
+// IGNORE_BACKEND_FIR: JVM_IR
 // MODULE: lib
 // FILE: lib.kt
 class A {
@@ -13,4 +14,4 @@ class A {
 // FILE: main.kt
 fun box(): String {
     return A().test()
-}
+}