Exclude temporary directories from pgindent

Exclude tmp_check and tmp_install from pgindent.  In a fully-built
tree, pgindent would spend a lot of time digging through these
directories and ends up re-indenting installed header files.

src/tools/pgindent/exclude_file_patterns

@@ -6,3 +6,5 @@
 /snowball/libstemmer/
 /pl/plperl/ppport\.h$
 /jit/llvmjit\.h$
+/tmp_check/
+/tmp_install/