[IMP] fields: improve performance of method `field.modified(records)`
[IMP] fields: improve performance of method `field.modified(records)`

Reduce the number of calls to `search` by grouping fields by model and by path.

microcom/odoo,hip-odoo/odoo,microcom/odoo,Elico-Corp/odoo_OCB,dfang/odoo,sysadminmatmoz/OCB,Elico-Corp/odoo_OCB,storm-computers/odoo,ygol/odoo,optima-ict/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,Elico-Corp/odoo_OCB,syci/OCB,ygol/odoo,hip-odoo/odoo,syci/OCB,storm-computers/odoo,optima-ict/odoo,bplancher/odoo,stephen144/odoo,dfang/odoo,syci/OCB,optima-ict/odoo,optima-ict/odoo,bplancher/odoo,stephen144/odoo,storm-computers/odoo,sysadminmatmoz/OCB,ygol/odoo,sysadminmatmoz/OCB,sysadminmatmoz/OCB,dfang/odoo,stephen144/odoo,hip-odoo/odoo,syci/OCB,optima-ict/odoo,sysadminmatmoz/OCB,dfang/odoo,bplancher/odoo,ygol/odoo,hip-odoo/odoo,dfang/odoo,microcom/odoo,microcom/odoo,storm-computers/odoo,optima-ict/odoo,ygol/odoo,syci/OCB,stephen144/odoo,hip-odoo/odoo,laslabs/odoo,dfang/odoo,syci/OCB,laslabs/odoo,bplancher/odoo,laslabs/odoo,microcom/odoo,sysadminmatmoz/OCB,bplancher/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,ygol/odoo,Elico-Corp/odoo_OCB,laslabs/odoo,laslabs/odoo,laslabs/odoo,stephen144/odoo,storm-computers/odoo,microcom/odoo,stephen144/odoo,ygol/odoo