UnitTestFrameworkPkg: Update to be more C11 compliant by using __func__

__FUNCTION__ is a pre-standard extension that gcc and Visual C++ among
others support, while __func__ was standardized in C99.

Since it's more standard, replace __FUNCTION__ with __func__ throughout
UnitTestFrameworkPkg.

Signed-off-by: Rebecca Cran <rebecca@bsdio.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

UnitTestFrameworkPkg/Library/UnitTestResultReportLib/UnitTestResultReportLibDebugLib.c

@@ -24,7 +24,7 @@ ReportPrint (
   VA_START (Marker, Format);
   Length = AsciiVSPrint (String, sizeof (String), Format, Marker);
   if (Length == 0) {
-    DEBUG ((DEBUG_ERROR, "%a formatted string is too long\n", __FUNCTION__));
+    DEBUG ((DEBUG_ERROR, "%a formatted string is too long\n", __func__));
   } else {
     DEBUG ((DEBUG_INFO, String));
   }