[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/diagnostics/tests/inline/vararg.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE -NOTHING_TO_INLINE
 
 inline fun inlineFun(s: (p: Int) -> Unit, noinline b: (p: Int) -> Unit) {
@@ -13,4 +14,4 @@ inline fun Function1<Int, Unit>.inlineExt(s: (p: Int) -> Unit, noinline b: (p: I
 
 inline fun subInline(vararg s: (p: Int) -> Unit) {}
 
-fun subNoInline(vararg s: (p: Int) -> Unit) {}
+fun subNoInline(vararg s: (p: Int) -> Unit) {}