Fix PCR reserved bits not being set correctly

[JPeMu]

This is a PR to address the issue reported in #893

The PCR value inside the TS Packet's Adaptation Field (where present) should be represented as:

program_clock_reference_base (33 bits)
reserved (6 bits)
program_clock_reference_extension (9 bits)

(Bit Positions)
.... ...4 .... .... .3.. .... ...2 .... .... .1.. .... ....
7654 3210 9876 5432 1098 7654 3210 9876 5432 1098 7654 3210
BBBB BBBB BBBB BBBB BBBB BBBB BBBB BBBB Brrr rrrE EEEE EEEE
----- most_significant_32bits_pcr -----|pcr_last_bit_reserved_and_pcr_extension
            (uint32_t)                         (uint16_t)

B = Base, r = reserved, E = Extension

The reserved bits should always be set to '1' per ISO 13818-1 therefore OR'ing a value of 0x7e00 is required to set these reserved bits imho.

Tony

[JPeMu]

This is my first PR here, so I apologise for the unittest fail back-and-forth. I've also had to update the golden files for .ts now that I understand how to run the full test suite as obviously this change affects some bits in the output files. Hope this is the correct approach?

[kqyang]

@JPeMu Thanks for the fix! And yes, that is the correct approach.

I'll merge it once the build-bots completes successfully.