[FIR] Improve diagnostic reporting & don't use error symbol for candidate if possible

Also introduce few new diagnostics:
- NONE_APPLICABLE more many inapplicable candidates
- HIDDEN for visible candidates

compiler/testData/ir/irText/expressions/sam/arrayAsVarargAfterSamArgument.kt

@@ -37,4 +37,4 @@ public class Test {
     }
     public Test(Runnable r, String... strs) {}
     public Test(Runnable r1, Runnable r2, String... strs) {}
-}
+}