EmulatorPkg: Fix VS2015 build when VS2017 also installed

EmulatorPkg: Fix VS2015 build when VS2017 also installed

https://bugzilla.tianocore.org/show_bug.cgi?id=2045

* Remove INTEL family flags that are no longer used.
* Remove [BuildOptions] statements that apply to all
  MSFT family tool chains
* Update [BuildOptions] for VS2015 and VS2015x86 tool
  chain tags to use the correct path to tools when
  multiple VS20xx tool chains are installed.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>