[builtins] Disable COMPILER_RT_CRT_USE_EH_FRAME_REGISTRY by default

[MaskRay]

Most of GCC's Linux targets have a link spec
%{!static|static-pie:--eh-frame-hdr} that doesn't pass --eh-frame-hdr
for -static links. -static links are supposed to utilize
__register_frame_info (called by crtbeginT.o, not by crtbegin.o or
crtbeginS.o) as a replacement.

compiler-rt crtbegin (not used with GCC) has some ehframe code, which is
not utilized because Clang driver unconditionally passes --eh-frame-hdr
for Linux targets, even for -static. In addition, LLVM libunwind
implements __register_frame_info as an empty stub.

Furthermore, in a non-static link, the __register_frame_info
references can cause an undesired weak dynamic symbol.

For now, just disable the config by default.

[MaskRay]

@xarblu

[thesamesam]

Thank you!

[mysterymath]

Hey, it looks like this breaks LLDB's test suite on Fuchsia's AArch64 builders: https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-linux-arm64/b8754880571862677073/overview

Reverting this change from the blamelist succeeds, and it's the only likely candidate change with that property.

[petrhosek]

Can we revert this change and then dig into the reason why these tests started failing? Our builders have been broken for an entire week and I'd like to avoid leaving them broken over the weekend.