[llvm-lit] Environment variable not found in compiler-rt subproject with lit internal shell

[Harini0924]

Currently, there are multiple environment variables are not recognized within the compiler-rt subproject, resulting in test failures when using the lit internal shell.
Example error message:

'XRAY_OPTIONS=patch_premain=false': command not found

This error indicates that the internal shell is misinterpreting environment variable assignments as commands, leading to these failures.

files with failures:

• compiler-rt/test/dfsan/custom.cpp
• compiler-rt/test/dfsan/flags.c
• compiler-rt/test/dfsan/fork.cpp
• compiler-rt/test/dfsan/origin_limit.c
• compiler-rt/test/msan/Linux/sendmsg.cpp
• compiler-rt/test/msan/chained_origin_empty_stack.cpp
• compiler-rt/test/msan/chained_origin_limits.cpp
• compiler-rt/test/msan/coverage-levels.cpp
• compiler-rt/test/msan/dtor-member.cpp
• compiler-rt/test/msan/fork.cpp
• compiler-rt/test/msan/interception_sigaction_test.cpp
• compiler-rt/test/msan/memcmp_test.cpp
• compiler-rt/test/msan/msan_check_mem_is_initialized.cpp
• compiler-rt/test/msan/poison_in_free.cpp
• compiler-rt/test/msan/print_stats.cpp
• compiler-rt/test/msan/recover-dso.cpp
• compiler-rt/test/msan/recover.cpp
• compiler-rt/test/msan/release_origin.c
• compiler-rt/test/msan/strcmp.c
• compiler-rt/test/msan/strndup.cpp
• compiler-rt/test/profile/Linux/instrprof-comdat.test
• compiler-rt/test/sanitizer_common/TestCases/Linux/signal_segv_handler.cpp
• compiler-rt/test/ubsan/TestCases/Misc/Linux/static-link.cpp
• compiler-rt/test/xray/TestCases/Posix/arg1-arg0-logging.cpp
• compiler-rt/test/xray/TestCases/Posix/arg1-logger.cpp
• compiler-rt/test/xray/TestCases/Posix/arg1-logging-implicit-this.cpp
• compiler-rt/test/xray/TestCases/Posix/argv0-log-file-name.cpp
• compiler-rt/test/xray/TestCases/Posix/coverage-sample.cpp
• compiler-rt/test/xray/TestCases/Posix/fdr-reinit.cpp
• compiler-rt/test/xray/TestCases/Posix/fixedsize-logging.cpp
• compiler-rt/test/xray/TestCases/Posix/func-id-utils.cpp
• compiler-rt/test/xray/TestCases/Posix/optional-inmemory-log.cpp
• compiler-rt/test/xray/TestCases/Posix/patching-unpatching.cpp
• compiler-rt/test/xray/TestCases/Posix/pic_test.cpp
• compiler-rt/test/xray/TestCases/Posix/typed-event-logging.cpp
• compiler-rt/test/nsan/Posix/tls_reuse.c
• compiler-rt/test/nsan/nan.cpp
• compiler-rt/test/nsan/softmax.cpp
• compiler-rt/test/nsan/sum.cpp
• compiler-rt/test/nsan/vec_sqrt_ext.cpp
• compiler-rt/test/fuzzer/out-of-process-fuzz.test
• compiler-rt/test/sanitizer_common/TestCases/sanitizer_coverage_allowlist_ignorelist.cpp
• compiler-rt/test/sanitizer_common/TestCases/sanitizer_coverage_symbolize.cpp
• compiler-rt/test/sanitizer_common/TestCases/sanitizer_coverage_trace_pc_guard-dso.cpp
• compiler-rt/test/sanitizer_common/TestCases/sanitizer_coverage_trace_pc_guard-init.cpp
• compiler-rt/test/sanitizer_common/TestCases/sanitizer_coverage_trace_pc_guard.cpp
• compiler-rt/test/nsan/vec_sqrt.cpp
• compiler-rt/test/xray/TestCases/Posix/fdr-single-thread.cpp