MDEV-12404: Add assertions about Index Condition Pushdown use

Add assertions about limitations one has when using Index Condition
Pushdown:
- add handler::assert_icp_limitations()
- call this function from functions that may attempt violations.

Verified that assert_icp_limitations() as well as calls to it are
compiled away in release build.

sql/handler.h

@@ -4772,6 +4772,8 @@ public:
    in_range_check_pushed_down= false;
  }
 
+ inline void assert_icp_limitations(uchar *buf);
+
  virtual void cancel_pushed_rowid_filter()
  {
    pushed_rowid_filter= NULL;