[lldb][test] Avoid namespace name colliding with dyld symbols in TestAbiTagLookup (#203984)

TestAbiTagLookup.py used `v1` as the inline namespace name. On macOS the
dyld shared cache contains two unrelated internal data symbols named
`v1` (one in dyld, one in libdyld.dylib). When evaluating
`v1::withImplicitTag(...)`, `ClangExpressionDeclMap` resolves `v1` as a
namespace correctly, but then still falls through to
`SymbolContext::FindBestGlobalDataSymbol`, which finds the two dyld
symbols and raises "Multiple internal symbols found for 'v1'", failing
the test.

Rename the inline namespace to `lldb_test_abi_tag_lookup_inline_ns` so
the test no longer collides with anything in dyld.

Add a new XFAIL test, namespace_data_symbol_collision, that reproduces
the underlying bug deterministically (without depending on `dyld`) by
linking two non-debug-info objects that each define a static data
symbol whose name matches a real namespace in main.cpp.

GitOrigin-RevId: af5aa17f44bf385e3cc9e2d9ffc2156e49f1071e