so far, we used a build pass only to retrieve accurate target
information from the exact evaluator. however, this is insufficient for
at least two reasons:
- the recently introduced postprocessing of RESOURCES in resources.prf
  is executed only during build passes
- some relevant variables are build pass specific, for example
  INCLUDEPATH when it includes RCC_DIR

an additional upside is that using the build pass' values is consistent
with qmake's vcxproj generation mode.

on the downside, the extra cumulative build pass adds 33% of pure
project evaluation time. however, this isn't as bad, as the pro files
are already loaded and parsed, and the expensive source file resolution
moves completely to the build pass.

the alternative of defeating the build pass logic (as lupdate does) is
not feasible, as we rely on accurate target information from an actual
build pass for the run configurations.

note that this all applies only to windows (and macos when explicitly
configured with -debug-and-release).

Task-number: QTCREATORBUG-16019
Change-Id: I8a97856b3b738aa1a581d24ba24bb3e7199d8078
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>