pgsql: Add install rules for Kerberos.pm and AdjustUpgrade.pm

Add install rules for Kerberos.pm and AdjustUpgrade.pm

For the same reasons as c3a0818460a8, these can be useful for
out-of-core extension testing. Kerberos.pm has been moved to its
current path recently in 9f899562d420, and AdjustUpgrade.pm has been
introduced in 52585f8f072a, still both lacked [un]installation rules for
both meson and configure.

Reported-by: Ashutosh Bapat
Discussion: /messages/by-id/ZozqzznkDhfCG7Ng@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1564339bfe23b2d1aa6403d6a08a7eaae0373cf9

Modified Files
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src/test/perl/Makefile | 4 ++++
src/test/perl/meson.build | 2 ++
2 files changed, 6 insertions(+)