[compiler-rt] [compiler-rt] Fix some tests to work with lit internal shell. (PR #160728)

[via llvm-commits]

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@@ -1,14 +1,14 @@
 # Check that libFuzzer honors SIGUSR1/SIGUSR2
 # Disabled on Windows which does not have SIGUSR1/SIGUSR2.
-REQUIRES: shell
 UNSUPPORTED: darwin, target={{.*windows.*}}, target=aarch64{{.*}}
 RUN: rm -rf %t
 RUN: mkdir -p %t
 RUN: %cpp_compiler %S/SleepOneSecondTest.cpp -o %t/ForkSIGUSR
 
-RUN: %run %t/ForkSIGUSR -fork=3 -ignore_crashes=1 2>%t/log & export PID=$!
+RUN: bash -c "nohup %run %t/ForkSIGUSR -fork=3 -ignore_crashes=1 2>%t/log &" | env
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cmtice wrote:

The internal shell doesn't directly handle '$' variables. It can't recognize '$!'.

https://github.com/llvm/llvm-project/pull/160728