[roll] Roll fuchsia [fidl] Move coding tables from fidlc to fidlgen_hlcpp

This CL moves the FIDL coding table generation from fidlc to the
fidlgen_hlcpp backend. Coding tables can be derived from the JSON IR,
and they are now only used by HLCPP. This has several benefits:

* Less code to maintain (this is +890 -3584 excluding goldens).
* Coding tables now use the same Go template system as everything else.
* Output gets formatted with clang-format like everything else.
* Reuses the padding mask logic used by C++ and Rust backends, recently
  refactored in I2bd96942322b8aba501469320e6e1dd12e1d6c4f.
* Fewer build targets (coding tables are now part of _hlcpp targets).

There are a few minor changes in the new coding tables:

* Can't flatten structs from external libraries since the JSON IR
  doesn't provide their fields.
* Forward declare everything instead of trying to emit types in order.
* Emit masks in hex instead of decimal.

This is part of a soft transition:

1. I3a441195ba496862ce38b0a32c40851eed0ced61: emit empty tables.c
2. update out-of-tree builds to include new file
3. (This CL) move code to new file
4. update out-of-tree builds to remove old file
5. Ic2faca1fe904eaa6c671302b29be50bfe21eac93: remove old file

Test: fx check-goldens fidlc
Test: fx check-goldens fidlgen_hlcpp
Test: fx test fidl
Original-Bug: 39388
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/946309
Original-Revision: 17a6cd4f5dddae5fa352ac6a2eb0c832510f4ca3
GitOrigin-RevId: 213923cf1a17576c86f1705be78c4dc3d8c239cc
Change-Id: I7920e1c8e967a45074a9f930c49c6c6b851962e1