Increase max path length. Add assert with descriptive comment.
Increase max path length. Add assert with descriptive comment.

Example of path from using blaze (262 chars):
/google/obj/workspace/2f021a0d86ffc22e41d10a5753a71978/a299d604-9113-4825-b67e-ee5d93cd51ca/blaze-out/gcc-4.X.Y-crosstool-v18-hybrid-grtev4-k8-fastbuild/bin/vr/internal/lullaby/examples/waypoint_deformation_anchored/waypoint_deformation_anchored.runfiles/google3

PiperOrigin-RevId: 162538916
Change-Id: I7a134f10a71256b2eefecf4c759f275650854a7c

google/fplbase,google/fplbase,google/fplbase,google/fplbase