[FR] Do basic checks before compilation

Hi! First, thanks for your work.
I tried to compile a sysimage and I ran into a trivial error:
```julia
julia> create_sysimage(["Plots", "FFTW"]; sysimage_path="~/Julia/test.so")
✔ [05m:22s] PackageCompiler: compiling incremental system image
ERROR: IOError: mkdir("~"; mode=0o777): permission denied (EACCES)
Stacktrace:
[1] uv_error
@ ./libuv.jl:97 [inlined]
[2] mkdir(path::String; mode::UInt16)
@ Base.Filesystem ./file.jl:185
[3] mkpath(path::String; mode::UInt16)
@ Base.Filesystem ./file.jl:241
[4] mkpath(path::String; mode::UInt16)
@ Base.Filesystem ./file.jl:239
[5] mkpath
@ ./file.jl:235 [inlined]
[6] create_sysimg_from_object_file(object_files::Vector{String}, sysimage_path::String; version::Nothing, compat_level::String, soname::Nothing)
@ PackageCompiler ~/.julia/packages/PackageCompiler/DKijm/src/PackageCompiler.jl:557
[7] create_sysimage(packages::Vector{String}; sysimage_path::String, project::String, precompile_execution_file::Vector{String}, precompile_statements_file::Vector{String}, incremental::Bool, filter_stdlibs::Bool, cpu_target::String, script::Nothing, sysimage_build_args::Cmd, include_transitive_dependencies::Bool, base_sysimage::Nothing, julia_init_c_file::Nothing, version::Nothing, soname::Nothing, compat_level::String, extra_precompiles::String)
@ PackageCompiler ~/.julia/packages/PackageCompiler/DKijm/src/PackageCompiler.jl:529
[8] top-level scope
@ REPL[10]:1

```
I assumed Julia would recognize `~` as the home directory. No big problem, but I wondered: in this case, compilation took only about 5 min. In bigger use case, it would be more, and that time is wasted if you have to reissue the command. In basic errors like this (mispelled paths, or permission denied), would it make sense to move these checks _before_ the compilation? In that way, the user could immediately correct the problem, and wait for compilation when they are (reasonably) confident the process will have success.

Start by tracing create_sysimage and create_sysimg_from_object_file in src/PackageCompiler.jl, especially the referenced lines around 529 and 557, and reproduce the failure with a sysimage_path containing `~`. Determine which path and permission checks can happen before compilation; done means invalid paths fail early while valid sysimage compilation still proceeds.

Written by the indexing model from the issue text.