Bump tornado from 6.4.1 to 6.4.2 #1406

Job	Run time
build	2m 2s
tests (//base/javacontainer/test:ExaStackTraceCleanerTest, ExaStackTraceCleanerTest)	48s
tests (//base/javacontainer/test:javacontainer-test-extractor-legacy, javacontainer-test-extracto...	3m 11s
tests (//base/javacontainer/test:javacontainer-test-extractor-v2, javacontainer-test-extractor-v2)	1m 16s
tests (//base/javacontainer/script_options/..., javacontainer-script_options)	1m 1s
tests (//base/exaudflib/test/..., exaudflib)	43s
tests (//base/script_options_parser/ctpg/..., script_options_parser_ctpg)	1m 53s
tests (//base/script_options_parser/legacy/..., script_options_parser_legacy)	1m 12s
tests (--run_under='valgrind --leak-check=yes' --config=valgrind //base/javacontainer/test:javaco...	1m 49s
tests (--run_under='valgrind --leak-check=yes' --config=valgrind //base/javacontainer/test:javaco...	1m 25s
tests (--run_under='valgrind --leak-check=yes' --config=valgrind //base/script_options_parser/ctp...	1m 39s
tests (--run_under='valgrind --leak-check=yes' --config=valgrind //base/script_options_parser/leg...	1m 27s
tests (--config=asan //base/javacontainer/test:javacontainer-test-extractor-legacy, javacontainer...	1m 26s
tests (--config=asan //base/javacontainer/test:javacontainer-test-extractor-v2, javacontainer-tes...	1m 27s
tests (--config=asan //base/script_options_parser/ctpg/..., script_options_parser_ctpg_with_asan)	1m 49s
tests (--config=asan //base/script_options_parser/legacy/..., script_options_parser_legacy_with_a...	1m 3s
	24m 11s

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