Inline QuicDefaultHasherImpl.
Inline QuicDefaultHasherImpl.

This is already defined as absl::Hash internally, in Chromium [1],
and in Envoy [2].

[1] https://source.chromium.org/chromium/chromium/src/+/main:net/quic/platform/impl/quic_containers_impl.h;l=18;drc=c0e19c27aa5b0db08d47c661e45c5cb552540f47
[2] https://github.com/envoyproxy/envoy/blob/a12869fa9e9add4301a700978d5489e6a0cc0526/source/common/quic/platform/quic_containers_impl.h#L26

PiperOrigin-RevId: 372200355
Change-Id: Ieb6593b2f63f16f34633a471c14e1ae9a882b3f9

google/quiche,google/quiche,google/quiche,google/quiche