update validation test

Author: Carl Peto

utils/build_swift/tests/expected_options.py

@@ -235,7 +235,7 @@
     'llvm_ninja_targets_for_cross_compile_hosts': [],
     'llvm_max_parallel_lto_link_jobs':
         defaults.LLVM_MAX_PARALLEL_LTO_LINK_JOBS,
-    'llvm_targets_to_build': 'X86;ARM;AArch64;PowerPC;SystemZ;Mips;RISCV;WebAssembly',
+    'llvm_targets_to_build': 'X86;ARM;AArch64;PowerPC;SystemZ;Mips;RISCV;WebAssembly;AVR',
     'tsan_libdispatch_test': False,
     'long_test': False,
     'lto_type': None,