Remove build systems other than CMake

Make it clear that CMake is the only supported build system.

Signed-off-by: Kevin Petit <kevin.petit@arm.com>

test_conformance/multiple_device_context/Jamfile

@@ -1,17 +0,0 @@
-project
-    : requirements
-      <toolset>gcc:<cflags>-xc++
-      <toolset>msvc:<cflags>"/TP"
-    ;
-
-exe test_multiple_device_context
-    : main.c
-      test_multiple_contexts.c
-      test_multiple_devices.cpp
-    ;
-
-install dist
-    : test_multiple_device_context
-    : <variant>debug:<location>$(DIST)/debug/tests/test_conformance/multiple_device_context
-      <variant>release:<location>$(DIST)/release/tests/test_conformance/multiple_device_context
-    ;

test_conformance/multiple_device_context/Makefile

@@ -1,46 +0,0 @@
-ifdef BUILD_WITH_ATF
-ATF = -framework ATF
-USE_ATF = -DUSE_ATF
-endif
-
-SRCS = main.c \
-		  test_multiple_contexts.c \
-		  test_multiple_devices.cpp \
-		  ../../test_common/harness/errorHelpers.c \
-		  ../../test_common/harness/threadTesting.c \
-		  ../../test_common/harness/testHarness.c \
-		  ../../test_common/harness/kernelHelpers.c \
-		  ../../test_common/harness/genericThread.cpp \
-                  ../../test_common/harness/mt19937.c \
-                  ../../test_common/harness/conversions.c \
-		  ../../test_common/harness/typeWrappers.cpp
-		  
-DEFINES = DONT_TEST_GARBAGE_POINTERS
-
-SOURCES = $(abspath $(SRCS))
-LIBPATH += -L/System/Library/Frameworks/OpenCL.framework/Libraries
-LIBPATH += -L.
-FRAMEWORK = $(SOURCES)
-HEADERS = 
-TARGET = test_multiples
-INCLUDE = 
-COMPILERFLAGS = -c -Wall -g -Wshorten-64-to-32
-CC = c++
-CFLAGS = $(COMPILERFLAGS) ${RC_CFLAGS} ${USE_ATF} $(DEFINES:%=-D%) $(INCLUDE)
-CXXFLAGS = $(COMPILERFLAGS) ${RC_CFLAGS} ${USE_ATF} $(DEFINES:%=-D%) $(INCLUDE)
-LIBRARIES = -framework OpenCL -framework OpenGL -framework GLUT -framework AppKit ${ATF}
-
-OBJECTS := ${SOURCES:.c=.o}
-OBJECTS := ${OBJECTS:.cpp=.o}
-
-TARGETOBJECT =
-all: $(TARGET)
-
-$(TARGET): $(OBJECTS)
-	$(CC) $(RC_CFLAGS) $(OBJECTS) -o $@ $(LIBPATH) $(LIBRARIES)
-
-clean:
-	rm -f $(TARGET) $(OBJECTS)
-
-.DEFAULT:
-	@echo The target \"$@\" does not exist in Makefile.