Remove ICU tests from default run

These tests require the test database to be in UTF8 encoding.  Until
there is a better solution, take them out of the default test set and
treat them like the existing collate.linux.utf8 test, meaning it has to
be selected manually.

doc/src/sgml/regress.sgml

@@ -264,10 +264,12 @@ make check EXTRA_TESTS=numeric_big
 </screen>
     To run the collation tests:
 <screen>
-make check EXTRA_TESTS=collate.linux.utf8 LANG=en_US.utf8
+make check EXTRA_TESTS='collate.icu.utf8 collate.linux.utf8' LANG=en_US.utf8
 </screen>
     The <literal>collate.linux.utf8</> test works only on Linux/glibc
-    platforms, and only when run in a database that uses UTF-8 encoding.
+    platforms.  The <literal>collate.icu.utf8</literal> test only works when
+    support for ICU was built.  Both tests will only succeed when run in a
+    database that uses UTF-8 encoding.
    </para>
   </sect2>
 

src/test/regress/GNUmakefile

@@ -125,9 +125,6 @@ tablespace-setup:
 ##
 
 REGRESS_OPTS = --dlpath=. $(EXTRA_REGRESS_OPTS)
-ifeq ($(with_icu),yes)
-override EXTRA_TESTS := collate.icu $(EXTRA_TESTS)
-endif
 
 check: all tablespace-setup
 	$(pg_regress_check) $(REGRESS_OPTS) --schedule=$(srcdir)/parallel_schedule $(MAXCONNOPT) $(EXTRA_TESTS)