[compiler-rt] Don't check COMPILER_RT_STANDALONE_BUILD for test deps

With https://github.com/llvm/llvm-project/pull/83088, we now need the
runtimes to be built before running test if
COMPILER_RT_TEST_STANDALONE_BUILD_LIBS is true, since otherwise we
get failures running `ninja check-all` such as the following:
```
/usr/bin/ld: cannot find .../compiler-rt/cmake-build-all-sanitizers/lib/linux/libclang_rt.fuzzer-x86_64.a: No such file or directory
/usr/bin/ld: cannot find .../compiler-rt/cmake-build-all-sanitizers/lib/linux/libclang_rt.xray-x86_64.a: No such file or directory
/usr/bin/ld: cannot find .../compiler-rt/cmake-build-all-sanitizers/lib/linux/libclang_rt.xray-basic-x86_64.a: No such file or directory
/usr/bin/ld: cannot find .../compiler-rt/cmake-build-all-sanitizers/lib/linux/libclang_rt.xray-fdr-x86_64.a: No such file or directory
```

This is a follow-up to 058e9b03 which started removing these checks
and it should make it easier to stop forcing COMPILER_RT_STANDALONE_BUILD
for runtimes builds in the future.

Reviewed By: vitalybuka

Pull Request: https://github.com/llvm/llvm-project/pull/83651