[IPU] restore dockerfile to gcc8.2 (#44909)

* restore to gcc8.2

* test=document_fix

tools/dockerfile/Dockerfile.ipu

@@ -25,10 +25,16 @@ RUN apt-get update && apt-get install -y curl wget vim git unzip unrar tar xz-ut
     openssl libffi-dev pciutils libblas-dev gfortran libblas3 liblapack-dev liblapack3 default-jre screen tmux gdb lldb gcc g++
 RUN apt-get update && apt-get install -y rdma-core librdmacm1
 
-# install g++-8
-RUN apt install g++-8 gcc-8 -y
-RUN ln -sf /usr/bin/gcc-8 /usr/bin/gcc
-RUN ln -sf /usr/bin/g++-8 /usr/bin/g++
+# Downgrade gcc&&g++
+WORKDIR /usr/bin
+COPY tools/dockerfile/build_scripts /build_scripts 
+RUN bash /build_scripts/install_gcc.sh gcc82 && rm -rf /build_scripts 
+RUN cp gcc gcc.bak && cp g++ g++.bak && rm gcc && rm g++ 
+RUN ln -s /usr/local/gcc-8.2/bin/gcc /usr/local/bin/gcc 
+RUN ln -s /usr/local/gcc-8.2/bin/g++ /usr/local/bin/g++ 
+RUN ln -s /usr/local/gcc-8.2/bin/gcc /usr/bin/gcc 
+RUN ln -s /usr/local/gcc-8.2/bin/g++ /usr/bin/g++ 
+ENV PATH=/usr/local/gcc-8.2/bin:$PATH 
 
 # install cmake
 WORKDIR /home