pgsql: Fix `trap` in a few shell scripts

Fix `trap` in a few shell scripts

The original `trap` lines in these scripts are incomplete: in case of
any signal, they delete the working directory but let the script run to
completion, which is useless because it will only proceed to complain
about the working directory being removed.  Add `exit` there, with the
original exit value (not rm's).

Since this is mostly just cosmetic, no backpatch.

Discussion: https://postgr.es/m/20220913181002.hzsosy7qkemb7ky7@alvherre.pgsql

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3d53b9ef1a4cda7b6303a0496f8531eceeef0e77

Modified Files
--------------
src/tools/find_static              | 2 +-
src/tools/make_ctags               | 2 +-
src/tools/pginclude/cpluspluscheck | 2 +-
src/tools/pginclude/headerscheck   | 6 +++---
src/tools/pgtest                   | 2 +-
5 files changed, 7 insertions(+), 7 deletions(-)