check_format: don't error if clang-format-9 is in PATH under home (#11449)
check_format: don't error if clang-format-9 is in PATH under home (#11449)

Signed-off-by: Greg Greenway <f58b4fce410ab27c1d5cc4afd1f2a190e9aa65c3@apple.com>
envoyproxy/envoy,lyft/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy,lyft/envoy,lyft/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy-wasm,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lizan/envoy,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy,lyft/envoy,lyft/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy-wasm,lizan/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,envoyproxy/envoy,lizan/envoy,lyft/envoy