Add support for --start-lib / --end-lib to Wasm LLD to omit the use of archives

[trybka]

Request implementing -start-lib and -end-lib flags for wasm-ld, analogous to the flags in ld.lld.

Object files after -start-lib are included in the link only when needed to resolve undefined symbols. (-end-lib returns command-line processing to the original behavior)

This mimics static libraries without needing to create an archive.

+cc: @sbc100 @walkingeyerobot @googlewalt

[llvmbot]

@llvm/issue-subscribers-lld-wasm

Author: Tom Rybka (trybka)

Request implementing `-start-lib` and `-end-lib` flags for `wasm-ld`, analogous to the flags in `ld.lld`.

Object files after -start-lib are included in the link only when needed to resolve undefined symbols. (-end-lib returns command-line processing to the original behavior)

This mimics static libraries without needing to create an archive.

+cc: @sbc100 @walkingeyerobot @googlewalt