arm64 support

[darkdragon-001]

Remove float equality test from configure.ac as it fails on arm64 and only succeeds on amd64 because of luck. It is skipped when cross-compiling anyways.
Based on the comment, weight_test.cc tests the same functionality but succeeds on arm64, so the autoconf failure is a false negative. Removing this test to fix build for arm64.

Testing procedure:

FROM debian:11

RUN apt-get update && \
  apt-get install -y --no-install-recommends \
  wget \
  bzip2 \
  unzip \
  xz-utils \
  g++ \
  make \
  cmake \
  git \
  python3 \
  python3-dev \
  python3-websockets \
  python3-setuptools \
  python3-pip \
  python3-wheel \
  python3-cffi \
  zlib1g-dev \
  automake \
  autoconf \
  libtool \
  pkg-config \
  ca-certificates \
  && rm -rf /var/lib/apt/lists/*

COPY . /opt/openfst
WORKDIR /opt/openfst
RUN autoreconf -i
RUN \
  ./configure --prefix=`pwd` \
  --enable-static --enable-shared --enable-far \
  --enable-ngram-fsts --disable-bin --enable-lookahead-fsts --with-pic \
  CXX="g++" \
  CXXFLAGS="-g -O3" \
  LDFLAGS="" \
  LIBS="-ldl"
RUN make -j $(nproc)
# This runs weight_test.cc 
RUN make -j 6 check
RUN make -j 6 install MAKEOVERRIDES=

Build and test on arm64 via qemu:

docker buildx build --platform linux/arm64 .

This is part of a my effort to enable arm64 builds in vosk:

• arm64 support #4
• arm64 support kaldi#8
• arm64 support vosk-server#270