[TypeScript] Add methods for BufferedTokenStream #1033

Job	Run time
cpp-lib-build (macos-11, clang, ON)	7m 53s
cpp-lib-build (macos-11, clang, OFF)	8m 18s
build (macos-11, tool)	1m 54s
cpp-lib-build (macos-11, gcc, ON)	18m 9s
build (macos-11, cpp)	32m 44s
cpp-lib-build (macos-11, gcc, OFF)	8m 6s
build (macos-11, csharp)	9m 26s
cpp-lib-build (ubuntu-20.04, clang, ON)	3m 14s
build (macos-11, dart)	2m 30s
cpp-lib-build (ubuntu-20.04, clang, OFF)	3m 14s
build (macos-11, go)	4m 36s
cpp-lib-build (ubuntu-20.04, gcc, ON)	4m 36s
build (macos-11, java)	2m 6s
cpp-lib-build (ubuntu-20.04, gcc, OFF)	5m 16s
build (macos-11, javascript)	2m 41s
cpp-lib-build (windows-2022, clang, ON)	4m 21s
build (macos-11, typescript)	18m 29s
cpp-lib-build (windows-2022, clang, OFF)	5m 42s
build (macos-11, php)	22s
cpp-lib-build (windows-2022, cl)	4m 26s
build (macos-11, python3)	1m 59s
build (ubuntu-20.04, tool)	1m 12s
build (ubuntu-20.04, cpp)	17m 10s
build (ubuntu-20.04, csharp)	4m 58s
build (ubuntu-20.04, dart)	3m 37s
build (ubuntu-20.04, go)	2m 23s
build (ubuntu-20.04, java)	1m 6s
build (ubuntu-20.04, javascript)	1m 24s
build (ubuntu-20.04, typescript)	9m 56s
build (ubuntu-20.04, php)	1m 47s
build (ubuntu-20.04, python3)	1m 14s
build (windows-2022, tool)	1m 39s
build (windows-2022, cpp)	22m 14s
build (windows-2022, csharp)	7m 21s
build (windows-2022, dart)	4m 16s
build (windows-2022, go)	5m 34s
build (windows-2022, java)	1m 53s
build (windows-2022, javascript)	2m 28s
build (windows-2022, typescript)	22m 35s
build (windows-2022, php)	2m 51s
build (windows-2022, python3)	1m 44s
	4h 27m 24s

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