Hi Raj,
If you have the same VLANs on both uplinks going to the SRX, then you can simply enable MSTP/RSTP on the SRX and this will stop loops forming.
Make sure that you set the bridge-priotiies across your devices so that your core switches are the spanning-tree root for each of the VLANs (you probably don't want the SRX to be root) and that one of the links to the SRX is blocking (not the link between core switches).
Mixing both Layer-2 (xSTP) and Layer-3 (VRRP) redundancy always comes with caveats. In a triangle configuration such as this, VRRP requires that spanning-tree has converged before it can fail over correctly. Also, you will require all VLANs trunked between both switches so that the VRRP master can still send heartbeats to the backup, without relying on the SRX to be up.
Hope this helps