[lldb][docs] Added LLDB_ENFORCE_STRICT_TEST_REQUIREMENTS for macOS configuration (llvm#130381)

Referenced here:
llvm#130171 (comment)

I think this will allow for issues relating towards missing modules for
test suites to be more manageable.

cc @adrian-prantl

---------

Co-authored-by: medievalghoul <[email protected]>

Author: wizardengineer

lldb/docs/resources/build.rst

@@ -340,7 +340,7 @@ On macOS the LLDB test suite requires libc++. Either add
   code-signed with identity ``lldb_codesign`` (see :ref:`CodeSigning`).
 * ``LLDB_USE_SYSTEM_DEBUGSERVER:BOOL``: Use the system's debugserver, so lldb is
   functional without setting up code-signing.
-
+* ``LLDB_ENFORCE_STRICT_TEST_REQUIREMENTS:BOOL``: Detect missing packages or modules at configuration time.
 
 .. _CMakeCaches: