[clang] [C++17] Support __GCC_[CON|DE]STRUCTIVE_SIZE (PR #89446)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

Here are the values that I found for GCC that don't match the defaults.

|Platform|Constructive|Destructive|Link
|-|-|-|-|
|ARM64|64|256|https://godbolt.org/z/G7arf9nPP|
|AVR|32|32|https://godbolt.org/z/Yq64f9Koj|
|BPF|32|32|https://godbolt.org/z/zezK71zoe|
|M68K|32|32|https://godbolt.org/z/h9f4vaYcs|
|mips|32|32|https://godbolt.org/z/v3nfPMx9b|
|mips64|32|32|https://godbolt.org/z/7G66rc4nY|
|power|32|32|https://godbolt.org/z/bWjdosE3f|
|power64|128|128|https://godbolt.org/z/jT86TMYTK|
|RISC-V 32-bit|32|32|https://godbolt.org/z/neErxEbWP|
|RISV-V 64-bit|32|32|https://godbolt.org/z/nG5zjjxdo|
|s390x|256|256|https://godbolt.org/z/j34f3eEMz|
|sparc|32|32|https://godbolt.org/z/96hscbesM|

Note, this is testing default configuration with no CPU tuning. I'll nab the values from here that I can map to our targets but target owners should validate these values and let me know if anything looks amiss.

https://github.com/llvm/llvm-project/pull/89446