Create symlinks for swift-frontend only once

[edymtt]

To achieve to, rely solely on add_swift_tool_symlink and
remove usages of swift_install_in_component.

This follows the intent of #6053.

Addresses rdar://101755409, supports rdar://101396797

[edymtt]

@swift-ci please smoke test

[edymtt]

@swift-ci please build toolchain

[edymtt]

I verified at desk that the generated build.ninja is the same, and that tools/driver/cmake_install.cmake drops the instructions related to swift_install_in_component

[edymtt]

@swift-ci please build toolchain Windows

[edymtt]

Hitting the following error in the testing of the Windows toolchain -- this seems unrelated to these changes, since it happens with other PRs (e.g. #37710)

Archiving artifacts ‘build/artifacts/*’ doesn’t match anything, but ‘*’ does. Perhaps that’s what you mean? ERROR: Step ‘Archive the artifacts’ failed: No artifacts found that match the file pattern "build/artifacts/*". Configuration error? 

[edymtt]

Checked that the generated toolchains still have the symlinks

# macOS % ls Library61768/Developer/Toolchains/swift-PR-61768-370.xctoolchain/usr/bin | grep swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 16:05 swift -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 16:05 swift-api-digester -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 16:05 swift-api-extract -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 16:05 swift-autolink-extract -> swift-frontend -rwxr-xr-x 1 emiotto admin 493436544 Oct 27 16:05 swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 16:05 swift-symbolgraph-extract -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 16:05 swiftc -> swift-frontend # Linux % ls usr61768/bin/ | grep swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 13:43 swift -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 13:43 swift-api-digester -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 13:43 swift-api-extract -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 13:43 swift-autolink-extract -> swift-frontend -rwxr-xr-x 1 emiotto admin 196556720 Oct 27 13:36 swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 13:43 swift-symbolgraph-extract -> swift-frontend lrwxr-xr-x 1 emiotto admin 14 Oct 27 13:43 swiftc -> swift-frontend 

[compnerd]

Do we still install the symbolic links when we now do a ninja install-distribution?

[compnerd]

Hmm, why were these duplicated?

[edymtt]

Not entirely sure why -- my best guess from looking at #10337 is that the original PR had some merge conflicts at one point, and leaving those instructions in there was one way to avoid that.

cc @CodaFi in case he remembers the context behind that change.