v0.30 updates: openssl, LLVM, and docker build layers

[jpmcb]

Issue number:

N/a - related to some build failures and optimizations

Description of changes:

- LLVM: Reverts to 14.0.6
- openssl: Removes 0056-strcasecmp.patch
- Dockerfile: Removes `--squash` for docker build and uses single layer for sdk

Testing done:

Coming soon!

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[jpmcb]

A bit more context:

• LLVM: Users saw some failures using v0.30 and v0.29 of the SDK where some LLVM symbols were missing. Reverting back to 14.0.6 fixed this but we need to investigate further to figure out what's going on here.
• OpenSSL: Users saw OPENSSL_strcasecmp being defined a second time. This drops that patch that re-defines this
• Dockerfile / docker build: The --squash flag is not supported with the DOCKERBUILD_KIT=1. So the workaround is to dump the final images into a single layered image at the end.

[jpculp]

• Build SDK x86_64 on x86_64
• Build SDK aarch64 on x86_64
• Build SDK aarch64 on aarch64
• Build SDK x86_64 on aarch64

Going to do some additional testing on Monday.

[jpculp]

Smoke tests passed for aws-k8s-1.24 (x86_64) and aws-ecs-1 (aarch64).