Make `no_cache=True` the default in `LinkerOptions`?

[leofang]

During the investigation of #920, I noticed that nvJitLink internally also has its own cache (likely sharing the driver cache). But it is confusing as a PTX developer when monitoring the info log: The first compilation I see this

self.get_info_log()='ptxas info    : 0 bytes gmem\nptxas info    : Function properties for add\nptxas         .     24 bytes stack frame, 16 bytes spill stores, 16 bytes spill loads\nptxas info    : Compile time = 2.002 ms\ninfo    : 16 bytes gmem\n\x00'

but second time onward it's only

self.get_info_log()='info    : 16 bytes gmem\n\x00'

Because the PTX is not re-compiled.

We already have a plan for caching (#176). I feel we should turn off nvJitLink's cache by default.