pgsql: Add an injection_points isolation test suite.

Add an injection_points isolation test suite.

Make the isolation harness recognize injection_points wait events as a
type of blocked state.  Test an extant inplace-update bug.

Reviewed by Robert Haas and Michael Paquier.

Discussion: https://postgr.es/m/20240512232923.aa.nmisch@google.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c35f419d6efbdf1a050250d84b687e6705917711

Modified Files
--------------
src/backend/access/heap/heapam.c                   |  2 +
src/backend/utils/adt/waitfuncs.c                  | 21 +++++-
src/test/modules/injection_points/Makefile         |  2 +
.../modules/injection_points/expected/inplace.out  | 43 +++++++++++
src/test/modules/injection_points/meson.build      |  5 ++
.../modules/injection_points/specs/inplace.spec    | 83 ++++++++++++++++++++++
6 files changed, 154 insertions(+), 2 deletions(-)