ci: todolist the remaining memcheck leak failures

The remaining leaks are small. Some are from exception handling
detailed at #1610 and being worked on in #2096.

This allows us to detect and new memory leaks introduced.

suppressions/nokogiri_ruby.supp

@@ -18,3 +18,136 @@
    fun:_dl_map_object
    ...
 }
+{
+  TODO xpath syntax errors raise and don't allow xmlXpathEval to clean up, see #2096 for related work
+  Memcheck:Leak
+  fun:malloc
+  fun:objspace_xmalloc0
+  fun:ruby_xmalloc0
+  fun:ruby_xmalloc_body
+  fun:ruby_xmalloc
+  fun:xmlXPathNewParserContext
+  fun:xmlXPathEval
+  fun:evaluate
+}
+{
+  TODO TestHtml5TreeConstructionNoscript01#test_0
+  Memcheck:Leak
+  fun:malloc
+  fun:gumbo_alloc
+  fun:gumbo_strdup
+  fun:handle_markup_declaration_open_state
+  fun:gumbo_lex
+  fun:gumbo_parse_with_options
+  fun:perform_parse
+  fun:parse
+}
+{
+  TODO TestHtml5TreeConstructionNoscript01#test_0
+  Memcheck:Leak
+  fun:malloc
+  fun:gumbo_alloc
+  fun:gumbo_string_buffer_to_string
+  fun:finish_temporary_buffer
+  fun:handle_doctype_name_state
+  fun:gumbo_lex
+  fun:gumbo_parse_with_options
+  fun:perform_parse
+  fun:parse
+}
+{
+  TODO
+  # 4 bytes in 1 blocks are definitely lost in loss record 1,080 of 38,167
+  Memcheck:Leak
+  fun:malloc
+  fun:objspace_xmalloc0
+  fun:ruby_xmalloc0
+  fun:ruby_xmalloc_body
+  fun:ruby_xmalloc
+  fun:xmlStrndup
+  fun:xmlXPathParseNCName
+  ...
+  fun:xmlXPathEval
+  fun:evaluate
+  # (xml_xpath_context.c:322)
+}
+{
+  TODO
+  # 44 bytes in 1 blocks are definitely lost in loss record 14,274 of 38,167
+  Memcheck:Leak
+  fun:malloc
+  fun:__vasprintf_internal
+  fun:xpath_generic_exception_handler
+  ...
+  fun:xmlXPathEval
+  fun:evaluate
+  # (xml_xpath_context.c:322)
+}
+{
+  TODO
+  # 128 bytes in 1 blocks are definitely lost in loss record 26,829 of 38,167
+  Memcheck:Leak
+  fun:malloc
+  fun:objspace_xmalloc0
+  fun:ruby_xmalloc0
+  fun:ruby_xmalloc_body
+  fun:ruby_xmalloc
+  fun:ar_alloc_table
+  fun:rb_hash_aset
+  fun:registr
+  # registr (xslt_stylesheet.c:246)
+}
+{
+  TODO
+  # 240 (120 direct, 120 indirect) bytes in 1 blocks are definitely lost in loss record 29,174 of 38,167
+  Memcheck:Leak
+  fun:malloc
+  fun:objspace_xmalloc0
+  fun:ruby_xmalloc0
+  fun:ruby_xmalloc_body
+  fun:ruby_xmalloc
+  fun:xmlNewDocNodeEatName
+  fun:xmlSAX2StartElementNs
+  ...
+  fun:xmlParseContent
+  fun:xmlParseDocument
+  fun:xmlReadMemory
+  fun:read_memory
+  # read_memory (xml_document.c:331)
+}
+{
+  TODO
+  # 240 (120 direct, 120 indirect) bytes in 1 blocks are definitely lost in loss record 30,299 of 39,687
+  # potentially a dup of the previous entry?
+  Memcheck:Leak
+  fun:malloc
+  fun:objspace_xmalloc0
+  fun:ruby_xmalloc0
+  fun:ruby_xmalloc_body
+  fun:ruby_xmalloc
+  fun:xmlNewNodeEatName
+  fun:xmlNewDocNodeEatName
+  fun:xmlSAX2StartElementNs
+  fun:xmlParseStartTag2
+  fun:xmlParseElementStart
+  fun:xmlParseContentInternal
+  fun:xmlParseElement
+  fun:xmlParseDocument
+  fun:xmlDoRead
+  fun:read_memory
+}
+{
+  TODO
+  # 1,800 (72 direct, 1,728 indirect) bytes in 1 blocks are definitely lost in loss record 36,149 of 38,167
+  # 2,216 (16 direct, 2,200 indirect) bytes in 1 blocks are definitely lost in loss record 36,463 of 38,167
+  Memcheck:Leak
+  fun:malloc
+  fun:objspace_xmalloc0
+  fun:ruby_xmalloc0
+  fun:ruby_xmalloc_body
+  fun:ruby_xmalloc
+  ...
+  fun:xmlXPathEval
+  fun:evaluate
+  # evaluate (xml_xpath_context.c:322)
+}