Don't build dummy objects when populating `ObTypeLookup` #3984

Job	Run time
build pgo-optimized on ${{ matrix.os }} / ${{ matrix.interpreter }}	0s
build on ${{ matrix.os }} (${{ matrix.target }} - ${{ matrix.interpreter \|\| 'all' }}${{ (((matrix.os == 'linux') && format(' - {0}', (((matrix.manylinux == 'auto') && 'manylinux') \|\| matrix.manylinux))) \|\| '') }})	0s
rust benchmarks	2m 56s
build sdist	12s
build-wasm-emscripten	2m 30s
coverage	2m 11s
lint	50s
test-debug 3.11	58s
test on ubuntu	2m 3s
test-debug pypy3.10	1m 32s
test on macos	4m 20s
test on windows	4m 20s
test-pydantic-integration	1m 34s
test 3.7	2m 3s
test 3.8	1m 59s
test 3.9	2m 15s
test 3.10	2m 9s
test 3.11	2m 7s
test 3.12	2m 12s
test pypy3.7	2m 38s
test pypy3.8	2m 37s
test pypy3.9	2m 25s
test pypy3.10	2m 48s
test build on ${{ matrix.os }}	0s
test build on ${{ matrix.target }}-${{ matrix.distro }}	0s
inspect-pypi-assets	0s
check	1s
release	0s
	46m 40s

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