Fix a brown paper bag error made by me in D129418. I didn't set
ASAN_INTERCEPT_VFORK correctly for loongarch64, but created an all-zero
object for __interception::real_vfork. This caused anything calling
vfork() to die instantly.
Fix this issue by setting ASAN_INTERCEPT_VFORK and remove the bad
all-zero definition. Other ports have an all-zero common definition but
we don't need it at least for now.
And, enable ASAN vfork test for loongarch64 to prevent regression in the
future.
Differential Revision: https://reviews.llvm.org/D137160
[11/11] patch series to port ASAN for riscv64
These changes allow using ASAN on RISCV64 architecture.
The majority of existing tests are passing. With few exceptions (see below).
Tests we run on qemu and on "HiFive Unleashed" board.
Tests run:
```
Asan-riscv64-inline-Test - pass
Asan-riscv64-inline-Noinst-Test - pass
Asan-riscv64-calls-Noinst-Test - pass
Asan-riscv64-calls-Test - pass
```
Lit tests:
```
RISCV64LinuxConfig (282 supported, few failures)
RISCV64LinuxDynamicConfig (289 supported, few failures)
```
Lit failures:
```
TestCases/malloc_context_size.cpp - asan works, but backtrace misses some calls
TestCases/Linux/malloc_delete_mismatch.cpp - asan works, but backtrace misses some calls
TestCases/Linux/static_tls.cpp - "Can't guess glibc version" (under debugging)
TestCases/asan_and_llvm_coverage_test.cpp - missing libclang_rt.profile-riscv64.a
```
These failures are under debugging currently and shall be addressed in a
subsequent commits.
Depends On D87581
Reviewed By: eugenis, vitalybuka
Differential Revision: https://reviews.llvm.org/D87582
