You may have noticed new warning message after installing ESXi 7.0, this can happen if your ESXi installation is on a smaller local disk (Nested ESXi Appliance would also be affected) which does not have enough capacity for setting up a core dump target or if ESXi is booting from USB which also does not support core dumps by default.
No coredump target has been configured. Host core dumps cannot be saved.
It is certainly recommended that you have a core dump target configured, especially for Production systems. However, if you wish to suppress the warning, there is an ESXi Advance Setting which you can toggle called UserVars.SuppressCoredumpWarning (can be configure using Embedded ESXi Host Client or vSphere UI in vCenter Server) as well as ESXCLI. Below is the command to suppress the warning:
esxcli system settings advanced set -o /UserVars/SuppressCoredumpWarning -i 1