Deduplicate test_basic test_fpmath (#1534)

Merge fpmath_float,fpmath_float2,fpmath_float4
as they share a lot of common code.

Signed-off-by: John Kesapides <john.kesapides@arm.com>

Signed-off-by: John Kesapides <john.kesapides@arm.com>

test_conformance/basic/CMakeLists.txt

@@ -2,7 +2,7 @@ set(MODULE_NAME BASIC)
 
 set(${MODULE_NAME}_SOURCES
     main.cpp
-    test_fpmath_float.cpp test_fpmath_float2.cpp test_fpmath_float4.cpp
+    test_fpmath_float.cpp
     test_intmath.cpp
     test_hiloeo.cpp test_local.cpp test_pointercast.cpp
     test_if.cpp test_loop.cpp