`nothing` in `report_invalidations`

[schillic]

The julia-invalidations script currently crashes.

ERROR: LoadError: FieldError: type Nothing has no field `name`; Nothing has no fields at all.
Stacktrace:
  [1] getproperty
    @ ./Base_compiler.jl:54 [inlined]
  [2] #12
    @ ~/.julia/packages/SnoopCompile/sSjKE/ext/SCPrettyTablesExt.jl:35 [inlined]

I think the problem is the same as in #447: inv.method below can be nothing.

SnoopCompile.jl/ext/SCPrettyTablesExt.jl

Lines 34 to 39 in 6cf031f

	meth_name = map(trees) do inv
	"$(inv.method.name)"
	end
	fileinfo = map(trees) do inv
	"$(process_filename(string(inv.method.file))):$(inv.method.line)"
	end