pgsql: Fix up recent breakage of headerscheck and cpluspluscheck.

Fix up recent breakage of headerscheck and cpluspluscheck.

headerscheck and cpluspluscheck should skip the recently-added
cmdtaglist.h header, since (like kwlist.h and some other similarly-
designed headers) it's not meant to be included standalone.

evtcache.h was missing an #include to support its usage of Bitmapset.

typecmds.h was missing an #include to support its usage of ParseState.

The first two of these were evidently oversights in commit 2f9661311.
I didn't track down exactly which change broke typecmds.h, but it
must have been some rearrangement in one of its existing inclusions,
because it's referenced ParseState for quite a long time and there
were not complaints from these checking programs before.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/d0587f52b3bb898db3c0011954de6ae9adc076c8

Modified Files
--------------
src/include/commands/typecmds.h | 2 +-
src/include/tcop/cmdtaglist.h | 2 +-
src/include/utils/evtcache.h | 1 +
src/tools/pginclude/cpluspluscheck | 1 +
src/tools/pginclude/headerscheck | 1 +
5 files changed, 5 insertions(+), 2 deletions(-)