[compiler-rt][asan][test] Set LD_LIBRARY_PATH_{32,64} on Solaris

The dynamically linked ASan tests rely on `LD_LIBRARY_PATH` to find
`libclang_rt.asan-*.so` at runtime.

However, the Solaris runtime linker `ld.so.1` also supports more specific
variables: `LD_LIBRARY_PATH_32` and `LD_LIBRARY_PATH_64` respectively.  If
those happen to be set, `LD_LIBRARY_PATH` is ignored.  In such a case, all
dynamically linked ASan tests `FAIL`.  For i386 alone, this affects about
200 tests.

The following patch fixes that by also setting `LD_LIBRARY_PATH_{32,64}` on
Solaris.

Tested on `amd64-pc-solaris2.11` both with only `LD_LIBRARY_PATH` set and
with `LD_LIBRARY_PATH_{32,64}` set too.

Differential Revision: https://reviews.llvm.org/D86333