[TypeScript] Add methods for BufferedTokenStream #1040

Job	Run time
cpp-lib-build (macos-11, clang, ON)	7m 29s
cpp-lib-build (macos-11, clang, OFF)	8m 19s
build (macos-11, tool)	2m 0s
cpp-lib-build (macos-11, gcc, ON)	7m 41s
build (macos-11, cpp)	33m 48s
cpp-lib-build (macos-11, gcc, OFF)	11m 15s
build (macos-11, csharp)	10m 55s
build (macos-11, dart)	5m 59s
cpp-lib-build (ubuntu-20.04, clang, ON)	4m 45s
build (macos-11, go)	4m 47s
cpp-lib-build (ubuntu-20.04, clang, OFF)	4m 52s
build (macos-11, java)	2m 12s
cpp-lib-build (ubuntu-20.04, gcc, ON)	3m 10s
cpp-lib-build (ubuntu-20.04, gcc, OFF)	3m 19s
build (macos-11, javascript)	2m 27s
cpp-lib-build (windows-2022, clang, ON)	4m 24s
build (macos-11, typescript)	20m 33s
cpp-lib-build (windows-2022, clang, OFF)	6m 37s
cpp-lib-build (windows-2022, cl)	5m 19s
build (macos-11, php)	23s
build (macos-11, python3)	1m 59s
build (ubuntu-20.04, tool)	59s
build (ubuntu-20.04, cpp)	17m 33s
build (ubuntu-20.04, csharp)	5m 9s
build (ubuntu-20.04, dart)	3m 49s
build (ubuntu-20.04, go)	2m 52s
build (ubuntu-20.04, java)	1m 13s
build (ubuntu-20.04, javascript)	1m 34s
build (ubuntu-20.04, typescript)	9m 45s
build (ubuntu-20.04, php)	1m 38s
build (ubuntu-20.04, python3)	1m 17s
build (windows-2022, tool)	2m 2s
build (windows-2022, cpp)	22m 38s
build (windows-2022, csharp)	7m 49s
build (windows-2022, dart)	4m 4s
build (windows-2022, go)	5m 44s
build (windows-2022, java)	1m 52s
build (windows-2022, javascript)	2m 34s
build (windows-2022, typescript)	21m 42s
build (windows-2022, php)	3m 59s
build (windows-2022, python3)	2m 2s
	4h 32m 28s

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