This library seems to be loaded only by the OpenCL implementation (libnvidia-opencl.so). It is not present in the driver package file NVIDIA-Linux-aarch64-460.56.run:
$ ./NVIDIA-Linux-aarch64-460.56.run --list | grep compiler -rwxr-xr-x dvs-builder/dvs-builder 9853360 2021-02-23 17:25 ./libnvidia-ptxjitcompiler.so.460.56
even though it is mentioned in the README.txt (line 700):
o Various libraries that are used internally by other driver components. These include '/usr/lib/libnvidia-cfg.so.460.56', '/usr/lib/libnvidia-compiler.so.460.56', '/usr/lib/libnvidia-eglcore.so.460.56', '/usr/lib/libnvidia-glcore.so.460.56', '/usr/lib/libnvidia-glsi.so.460.56', '/usr/lib/libnvidia-glvkspirv.so.460.56', '/usr/lib/libnvidia-rtcore.so.460.56', '/usr/lib/libnvidia-cbl.so.460.56', and '/usr/lib/libnvidia-allocator.so.460.56'.
I spot-checked a few older versions of the aarch64 driver from the archives and none of them include this library.
Without this library, the OpenCL implementation can’t compile any compute kernels: A simple test app will try to load libnvidia-compiler.so when calling clBuildProgram (verified by strace) – after that library fails to load, it returns CL_BUILD_PROGRAM_FAILURE.