Remove flags from ClangLibToolingUnknownCflags

This commit removes flags from ClangLibToolingUnknownCflags.  These
flags were added to workaround an old version of clang in
`external/clang`.  Since we have updated to clang-r339409b, we don't
need these workaround anymore.

Bug: 117764794
Test: development/vndk/tools/header-checker/utils/create_reference_dumps.py
Change-Id: Ifbeebf05df5c08ee3bb7d489f39250d8fd5f5acf
diff --git a/cc/config/clang.go b/cc/config/clang.go
index 5cf2421..b58223f 100644
--- a/cc/config/clang.go
+++ b/cc/config/clang.go
@@ -92,12 +92,7 @@
 	"-Wl,-m,aarch64_elf64_le_vec",
 })
 
-var ClangLibToolingUnknownCflags = []string{
-	// Remove -flto and other flto dependent flags.
-	"-flto*",
-	"-fsanitize*",
-	"-fwhole-program-vtables",
-}
+var ClangLibToolingUnknownCflags []string = nil
 
 func init() {
 	pctx.StaticVariable("ClangExtraCflags", strings.Join([]string{