FIR DFA: make continue jump to condition entry, not loop entry

It's also not a backwards jump in do-while, unless it's in the loop's
condition, which is a stupid "feature" IMO. As you can probably tell
from the comments added in this commit.

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/35.fir.kt

@@ -70,7 +70,7 @@ fun case_6(x: Any?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>x<!>.equals(10)
     } while (false)
 
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>x<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>x<!>
 }
 
 // TESTCASE NUMBER: 7