CppTools: Introduce HeaderPathFilter

We went the filtering of the header path outside of the compiler options
builder so merge the PCHs.

Task-number: QTCREATORBUG-21693
Change-Id: Ia1126813a5049e39d7c6e7d60bf449aa17012d02
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/plugins/cpptools/cpptoolsunittestfiles.pri

@@ -13,6 +13,7 @@ HEADERS += \
     $$PWD/projectinfo.h \
     $$PWD/cppprojectinfogenerator.cpp \
     $$PWD/cppprojectpartchooser.h \
+    $$PWD/headerpathfilter.h
 
 SOURCES += \
     $$PWD/cppprojectfile.cpp \
@@ -23,3 +24,4 @@ SOURCES += \
     $$PWD/projectinfo.cpp \
     $$PWD/cppprojectinfogenerator.cpp \
     $$PWD/cppprojectpartchooser.cpp \
+    $$PWD/headerpathfilter.cpp