fix(util): handle known UFCS corner cases

[JohelEGP]

Resolves #854.
Resolves #550.
Resolves #509. Resolves #769.
Resolves #497. Resolves #439. Closes #490. And discussion #810.
Resolves #496.
Resolves #493.
Provides a better name lookup implementation for #533.

Testing summary:

100% tests passed, 0 tests failed out of 858

Total Test time (real) =  47.47 sec

Acknowledgements:

• Tested thanks to https://github.com/modern-cmake/cppfront.
• The commit message uses Conventional Commits 1.0.0.

Status:

Test (*-bugfix-for-ufcs-*)	GCC 🐂	Clang 🐉	MSVC 🗔	Compiler Explorer
mixed-*-non-local	10 ✅ 11-14 ❌ᵈ	12 ❌ᵉ 13 ✅	✅	🐂 10 , 🐲 12 https://cpp1.godbolt.org/z/Mb9nhzxhh 🐂 11 , 🐲 13 https://cpp1.godbolt.org/z/19d4xaW5E 💼 https://cpp1.godbolt.org/z/rrTjhcbj7
pure2-*-arguments	10 ✅	12 ✅	✅	https://cpp1.godbolt.org/z/njP74b7PW 💼 https://cpp1.godbolt.org/z/G6se4rnzr
pure2-*-name-lookup	10 ✅	12 ✅	✅ᵃ	https://cpp1.godbolt.org/z/aWcvG9G1x 💼 https://cpp1.godbolt.org/z/7cqszTnbY
pure2-*-noexcept	10 ❌ᵇ 11 ✅	12 ❌ᵉ 13 ✅	✅	🐂 10 , 🐲 12 https://cpp1.godbolt.org/z/8ecedrz9s 🐂 11 , 🐲 13 https://cpp1.godbolt.org/z/rxxGf7vWP 💼 https://cpp1.godbolt.org/z/qMsseKKqY
pure2-*-sfinae	10 ✅	12 ❌ᵉ 13 ❌ᶜ 14 ✅	✅	🐲 12 https://cpp1.godbolt.org/z/8s7P87YvT 🐲 14 https://cpp1.godbolt.org/z/69Trr5EYd 💼 https://cpp1.godbolt.org/z/Wx6hrdeT6

✅ᵃ: After disabling various tests in pure2-*-name-lookup.
❌ᵇ: GCC BUG101043 (the workaround makes it always potentially-throwing).
❌ᶜ: Clang 13 bug (error: static_assert expression is not an integral constant expression, https://cpp1.godbolt.org/z/WcEqYx8sG).
❌ᵈ: GCC BUG109781 (GCC bug on UFCS use).
❌ᵉ: Clang 12 doesn't support lambdas in unevaluated contexts.

[JohelEGP]

fix(cpp1): handle known UFCS corner cases

Except for
3.2.int() (https://cpp2.godbolt.org/z/e3av4svTs),
#855,
#807,
#788,
#748?,
#555, and
#542 (comment) (not in main).

[JohelEGP]

Done.

[hsutter]

Thanks! 🎉

[JohelEGP]

This seems to be accepted now: https://cpp1.godbolt.org/z/dTsWzfMcd.