Backport fixes for aarch64-pc-windows-msvc#45

Merged

alexcrichton merged 3 commits intorust-lang:rustc/9.0-2019-12-19from danielframpton:rustc/aarch64-windows-backport-llvm9

Apr 2, 2020

+222-71

Commits on Apr 2, 2020

[CodeView] Add pragma push/pop_macro for ARM64_FPSR to enum header

mstorsjo
authored and
danielframpton
committed
[AArch64] Fix mismatch in prologue and epilogue for funclets on Windows
danielframpton
committed
[AArch64] Change AArch64 Windows EH UnwindHelp object to be a fixed object
danielframpton
committed