Standardize the error messages generated by constraint failures to a format

of "$TYPE constraint failed: $DETAIL".  This involves many changes to the
expected output of test cases.

FossilOrigin-Name: 54b221929744b1bcdbcc2030fef2e510618afd41

src/vdbeaux.c

@@ -2198,7 +2198,7 @@ int sqlite3VdbeCheckFk(Vdbe *p, int deferred){
   ){
     p->rc = SQLITE_CONSTRAINT_FOREIGNKEY;
     p->errorAction = OE_Abort;
-    sqlite3SetString(&p->zErrMsg, db, "foreign key constraint failed");
+    sqlite3SetString(&p->zErrMsg, db, "FOREIGN KEY constraint failed");
     return SQLITE_ERROR;
   }
   return SQLITE_OK;