[llvm-lit] Add REQUIRES: shell to BOLT permission test for lit internal shell (#103012)

This patch adds the `REQUIRES: shell` directive to the BOLT permission
test to ensure it only runs in environments with a full-featured
Unix-like shell. This change is necessary because the test relies on
advanced shell capabilities that are not supported by lit's internal
shell.

**Reasoning:** The BOLT permission test uses features like running
commands in the background with `&`, performing arithmetic operations,
and handling special number formats (octal). These features require a
more capable shell than what lit's internal shell provides. Without a
proper shell, the test could fail or behave unpredictably.

This change is relevant for enabling the lit internal shell by default,
as outlined in [[RFC] Enabling the Lit Internal Shell by
Default](https://discourse.llvm.org/t/rfc-enabling-the-lit-internal-shell-by-default/80179)

Author: Harini0924

bolt/test/permission.test

@@ -4,7 +4,7 @@
 # This test performs a logical AND operation on the results of the `stat -c %a
 # %t.bolt` and `umask` commands (both results are displayed in octal), and
 # checks whether the result is equal to 0.
-REQUIRES: system-linux
+REQUIRES: shell, system-linux
 
 RUN: %clang %cflags %p/Inputs/hello.c -o %t -Wl,-q
 RUN: llvm-bolt %t -o %t.bolt