Fix some violations of ql/counting-to-zero.

Author: michaelnebel

cpp/ql/lib/semmle/code/cpp/valuenumbering/HashCons.qll

@@ -648,7 +648,7 @@ private predicate mk_UuidofOperator(Type t, UuidofOperator e) {
 }
 
 private predicate analyzableTypeidType(TypeidOperator e) {
-  count(e.getAChild()) = 0 and
+  not exists(e.getAChild()) and
   strictcount(e.getResultType()) = 1
 }
 

cpp/ql/src/experimental/Likely Bugs/RedundantNullCheckParam.ql

@@ -47,7 +47,7 @@ where
   // for a function parameter
   unchecked.getTarget() = param and
   // this function parameter is not overwritten
-  count(param.getAnAssignment()) = 0 and
+  not exists(param.getAnAssignment()) and
   check.getTarget() = param and
   // which is once checked
   candidateResultChecked(check, eqop) and

java/ql/lib/semmle/code/java/frameworks/javaee/ejb/EJB.qll

@@ -35,14 +35,14 @@ class SessionEjb extends EJB {
     // Either the EJB does not declare any business interfaces explicitly
     // and implements a single interface candidate,
     // which is then considered to be the business interface...
-    count(this.getAnExplicitBusinessInterface()) = 0 and
+    not exists(this.getAnExplicitBusinessInterface()) and
     count(this.getAnImplementedBusinessInterfaceCandidate()) = 1 and
     result = this.getAnImplementedBusinessInterfaceCandidate()
     or
     // ...or each business interface needs to be declared explicitly.
     (
       count(this.getAnImplementedBusinessInterfaceCandidate()) != 1 or
-      count(this.getAnExplicitBusinessInterface()) != 0
+      exists(this.getAnExplicitBusinessInterface())
     ) and
     result = this.getAnExplicitBusinessInterface()
   }

java/ql/src/Likely Bugs/Termination/SpinOnField.ql

@@ -33,8 +33,8 @@ class Empty extends Stmt {
 class EmptyLoop extends Stmt {
   EmptyLoop() {
     exists(ForStmt stmt | stmt = this |
-      count(stmt.getAnInit()) = 0 and
-      count(stmt.getAnUpdate()) = 0 and
+      not exists(stmt.getAnInit()) and
+      not exists(stmt.getAnUpdate()) and
       stmt.getStmt() instanceof Empty
     )
     or