Improve test for CONVERT() with GB18030 <-> UTF8.

Add a bit of coverage of high code points.

Arjen Nienhuis

src/test/regress/expected/conversion.out

@@ -523,17 +523,17 @@ SELECT CONVERT('foo', 'UTF8', 'EUC_TW');
 (1 row)
 
 -- GB18030 --> UTF8
-SELECT CONVERT('foo', 'GB18030', 'UTF8');
- convert 
----------
- foo
+SELECT CONVERT('Postgres \247\343\247\335\247\340\247\337 \2249\3138 \317\363 \250\246le\2010\2747phant', 'GB18030', 'UTF8');
+                                             convert                                             
+-------------------------------------------------------------------------------------------------
+ Postgres \321\201\320\273\320\276\320\275 \360\237\220\230 \350\261\241 \303\251le\314\201phant
 (1 row)
 
 -- UTF8 --> GB18030
-SELECT CONVERT('foo', 'UTF8', 'GB18030');
- convert 
----------
- foo
+SELECT CONVERT('Postgres \321\201\320\273\320\276\320\275 \360\237\220\230 \350\261\241 \303\251le\314\201phant', 'UTF-8', 'GB18030');
+                                         convert                                         
+-----------------------------------------------------------------------------------------
+ Postgres \247\343\247\335\247\340\247\337 \2249\3138 \317\363 \250\246le\2010\2747phant
 (1 row)
 
 -- GBK --> UTF8

src/test/regress/sql/conversion.sql

@@ -171,9 +171,9 @@ SELECT CONVERT('foo', 'EUC_TW', 'UTF8');
 -- UTF8 --> EUC_TW
 SELECT CONVERT('foo', 'UTF8', 'EUC_TW');
 -- GB18030 --> UTF8
-SELECT CONVERT('foo', 'GB18030', 'UTF8');
+SELECT CONVERT('Postgres \247\343\247\335\247\340\247\337 \2249\3138 \317\363 \250\246le\2010\2747phant', 'GB18030', 'UTF8');
 -- UTF8 --> GB18030
-SELECT CONVERT('foo', 'UTF8', 'GB18030');
+SELECT CONVERT('Postgres \321\201\320\273\320\276\320\275 \360\237\220\230 \350\261\241 \303\251le\314\201phant', 'UTF-8', 'GB18030');
 -- GBK --> UTF8
 SELECT CONVERT('foo', 'GBK', 'UTF8');
 -- UTF8 --> GBK