[compiler-rt] [sanitizer] Remove GetCurrentThread nullness checks from Allocate (PR #102828)

[Steven Wu via llvm-commits]

cachemeifyoucan wrote:

This breaks Darwin bots: https://green.lab.llvm.org/job/llvm.org/job/clang-stage1-RA/1753/

```
GTEST_OUTPUT=json:/Users/ec2-user/jenkins/workspace/llvm.org/clang-stage1-RA/clang-build/tools/clang/runtime/compiler-rt-bins/lib/asan/tests/X86_64HDarwinConfig/./Asan-x86_64h-calls-Noinst-Test-AddressSanitizer-Unit-90874-10-16.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=16 GTEST_SHARD_INDEX=10 /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage1-RA/clang-build/tools/clang/runtime/compiler-rt-bins/lib/asan/tests/X86_64HDarwinConfig/./Asan-x86_64h-calls-Noinst-Test
--

Note: This is test shard 11 of 16.
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from AddressSanitizer
[ RUN      ] AddressSanitizer.ThreadedMallocStressTest
AddressSanitizerAddressSanitizerAddressSanitizerAddressSanitizer:DEADLYSIGNAL
:DEADLYSIGNAL
:DEADLYSIGNAL
:DEADLYSIGNAL
=================================================================
==92755==ERROR: AddressSanitizer: SEGV on unknown address 0x000000005e40 (pc 0x00010fa7eff8 bp 0x7000043ca630 sp 0x7000043ca600 T-1)
==92755==The signal is caused by a READ memory access.
    <empty stack>

==92755==Register values:
rax = 0x0000000000005d70  rbx = 0x0000000000000017  rcx = 0x0000000000000008  rdx = 0x0000000000000020  
rdi = 0x000000010fbb5eb8  rsi = 0x00000000000000d0  rbp = 0x00007000043ca630  rsp = 0x00007000043ca600  
 r8 = 0x0000000000000002   r9 = 0x0000000000000001  r10 = 0x00007ff7b04d6248  r11 = 0x0000000000000202  
r12 = 0x0000000000000008  r13 = 0x0000000000000080  r14 = 0xfffffffffffffff8  r15 = 0x0000000000005e40  
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV
==92755==ABORTING

--
exit: 1
--
shard JSON output does not exist: /Users/ec2-user/jenkins/workspace/llvm.org/clang-stage1-RA/clang-build/tools/clang/runtime/compiler-rt-bins/lib/asan/tests/X86_64HDarwinConfig/./Asan-x86_64h-calls-Noinst-Test-AddressSanitizer-Unit-90874-10-16.json
```

Maybe revert?

https://github.com/llvm/llvm-project/pull/102828