Skip unnecessary source level queries where possible

[mbien]

Run javac profile queries only for java 8 targets which is the only java version where profiles existed.

Skip over query code in MavenSourceLevelImpl if the result value is already known. Add fast path for files outside of test dirs.

[neilcsmith-net]

Generally looks good.

Add fast path for files outside of test dirs.

Is there much difference with the fast path? Do we support custom paths elsewhere anyway? eg. assuming the path contains "test" might reach edge cases with things like https://maven.apache.org/whatsnewinmaven4.html#new-way-to-declare-source-directories ??

[mbien]

if you take a look at getSourceRoots and getGeneratedSourceRoots which are both called from within the if block. They build the path with /test/. So its already a given that test must be in the path.

[neilcsmith-net]

I already looked at them. Are you sure getSourceRoots does that for the paths reported by Maven itself? It does for JavaLikeRootProvider results.