FIR checker: introduce top-level function checker

compiler/fir/analysis-tests/testData/resolve/arguments/operatorsOverLiterals.fir.txt

@@ -19,7 +19,8 @@ FILE: operatorsOverLiterals.kt
     }
     public final fun R|kotlin/Int|.bar(): R|kotlin/Int| {
     }
-    public final fun R|kotlin/Int|.baz(): R|kotlin/Int|
+    public final fun R|kotlin/Int|.baz(): R|kotlin/Int| {
+    }
     public final fun R|kotlin/Byte|.baz(): R|kotlin/Byte| {
     }
     public final fun test_3(): R|kotlin/Unit| {

compiler/fir/analysis-tests/testData/resolve/arguments/operatorsOverLiterals.kt

@@ -20,7 +20,7 @@ fun test_2(n: Int) {
 
 fun Int.bar(): Int {}
 
-fun Int.baz(): Int
+fun Int.baz(): Int {}
 fun Byte.baz(): Byte {}
 
 fun test_3() {

compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.fir.txt

@@ -111,7 +111,8 @@ FILE: conflictingOverloads.kt
         }
 
     }
-    public final fun mest(): R|kotlin/Unit|
+    public final fun mest(): R|kotlin/Unit| {
+    }
     public final class mest : R|kotlin/Any| {
         public constructor(): R|mest| {
             super<R|kotlin/Any|>()

compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.kt

@@ -59,7 +59,7 @@ class L {
     fun B.foo() {}
 }
 
-fun mest()
+fun mest() {}
 
 class mest
 

compiler/fir/analysis-tests/testData/resolve/intersectionTypes.kt

@@ -5,7 +5,7 @@ interface B
 class Clazz1 : A, B
 class Clazz2 : A, B
 
-fun <K> select(x: K, y: K): K
+<!NON_MEMBER_FUNCTION_NO_BODY!>fun <K> select(x: K, y: K): K<!>
 
 fun test() = select(Clazz1(), Clazz2())
 

compiler/fir/analysis-tests/testData/resolve/multifile/simpleStarImport.kt

@@ -14,7 +14,7 @@ package a.d
 
 import b.d.*
 
-fun foo(arg: Other): Another
+<!NON_MEMBER_FUNCTION_NO_BODY!>fun foo(arg: Other): Another<!>
 
 fun bar() {
     baz()