Enable ccache for lldb-(arm/aarch64)-ubuntu builders

This patch enables the use of ccache by LLDB ARM/AArch64 buildbots.
I have added following cmake switches to lldb-(arm/aarch64)-ubuntu
builders:
-DCMAKE_C_COMPILER_LAUNCHER=ccache
-DCMAKE_CXX_COMPILER_LAUNCHER=ccache
1 file changed