Remove unanchored "error" string from symtab2gb test specs

tautschnig · tautschnig · commit c927ea963a7a · 2024-04-30T10:47:45.000Z
This string would (also) match the very legitimate output "Building
error trace".
diff --git a/regression/symtab2gb/multiple_symtabs/test.desc b/regression/symtab2gb/multiple_symtabs/test.desc
@@ -7,4 +7,3 @@ user.json_symtab library.json_symtab
 ^\[2\] file library.adb line \d+ assertion: FAILURE$
 ^VERIFICATION FAILED$
 --
-error
diff --git a/regression/symtab2gb/single_symtab/test.desc b/regression/symtab2gb/single_symtab/test.desc
@@ -7,4 +7,3 @@ entry_point.json_symtab
 ^\[2\] file entry_point.adb line \d+ assertion: SUCCESS$
 ^VERIFICATION FAILED$
 --
-error
