Replace some FIR syntax errors with more proper diagnostics

compiler/testData/diagnostics/tests/BreakContinue.fir.kt

@@ -3,26 +3,26 @@ class C {
     fun f (a : Boolean, b : Boolean) {
         b@ while (true)
           a@ {
-            break@f
+            <!NOT_A_LOOP_LABEL!>break@f<!>
             break
             break@b
-            break@a
+            <!NOT_A_LOOP_LABEL!>break@a<!>
           }
 
-        continue
+        <!BREAK_OR_CONTINUE_OUTSIDE_A_LOOP!>continue<!>
 
         b@ while (true)
           a@ {
-            continue@f
+            <!NOT_A_LOOP_LABEL!>continue@f<!>
             continue
             continue@b
-            continue@a
+            <!NOT_A_LOOP_LABEL!>continue@a<!>
           }
 
-        break
+        <!BREAK_OR_CONTINUE_OUTSIDE_A_LOOP!>break<!>
 
-        continue@f
-        break@f
+        <!BREAK_OR_CONTINUE_OUTSIDE_A_LOOP!>continue@f<!>
+        <!BREAK_OR_CONTINUE_OUTSIDE_A_LOOP!>break@f<!>
     }
 
     fun containsBreak(a: String?, b: String?) {
@@ -50,7 +50,7 @@ class C {
 
     fun containsIllegalBreak(a: String?) {
         loop@ while(a == null) {
-            break@label
+            <!NOT_A_LOOP_LABEL!>break@label<!>
         }
         a.compareTo("2")
     }
@@ -78,7 +78,7 @@ class C {
             l@ for (el in array) {
                 break
             }
-            if (true) break else break@l
+            if (true) break else <!NOT_A_LOOP_LABEL!>break@l<!>
         }
         a.<!INAPPLICABLE_CANDIDATE!>compareTo<!>("2")
     }
@@ -86,7 +86,7 @@ class C {
     fun twoLabelsOnLoop() {
         label1@ label2@ for (i in 1..100) {
             if (i > 0) {
-                break@label1
+                <!NOT_A_LOOP_LABEL!>break@label1<!>
             }
             else {
                 break@label2