Remove clang indirection without affecting build.ninja

Remove cflags that are not handled by clang from the global defaults,
and remove calls to ClangFilterUnknownCflags.

Squash lists of clang-specific default flags into the main default
flags lists.

Rename Toolchain.Clang*flags to Toolchain.*flags.

Rename Go variables with Clang in the name that have no non-Clang
equivalent.

Remove unused ninja variables.

Bug: 68947919
Test: no change to build.ninja for aosp_cf_x86_64_phone-userdebug or aosp_crosshatch-userdebug
Change-Id: Id287945315d53e5eaef197adbbb4f1302f2e3680

cc/config/clang.go

@@ -80,12 +80,6 @@ var ClangUnknownCflags = sorted([]string{
 	"--enable-stdcall-fixup",
 })
 
-// Ldflags that should be filtered out when linking with clang lld
-var ClangUnknownLldflags = sorted([]string{
-	"-Wl,--fix-cortex-a8",
-	"-Wl,--no-fix-cortex-a8",
-})
-
 var ClangLibToolingUnknownCflags = sorted([]string{})
 
 // List of tidy checks that should be disabled globally. When the compiler is
@@ -255,26 +249,10 @@ func ClangRewriteTidyChecks(checks []string) []string {
 	return result
 }
 
-func ClangFilterUnknownLldflags(lldflags []string) []string {
-	result, _ := android.FilterList(lldflags, ClangUnknownLldflags)
-	return result
-}
-
 func ClangLibToolingFilterUnknownCflags(libToolingFlags []string) []string {
 	return android.RemoveListFromList(libToolingFlags, ClangLibToolingUnknownCflags)
 }
 
-func inListSorted(s string, list []string) bool {
-	for _, l := range list {
-		if s == l {
-			return true
-		} else if s < l {
-			return false
-		}
-	}
-	return false
-}
-
 func sorted(list []string) []string {
 	sort.Strings(list)
 	return list