Remove unnecessary TODO from ConstantExpression.h

We intend to have the method isValidEnumStorageType virtual
and attached to every method. This makes EnumType not have
to care about what underlying scalar type it is.

Further, making bool allowed as an enum storage type doesn't
add much value.

Test: none
Bug: 64358435
Change-Id: Ibdcffbafb380d9cfc50b7c1dbb9abb72f11c4293
diff --git a/ConstantExpression.cpp b/ConstantExpression.cpp
index 5f022c8..b6857a7 100644
--- a/ConstantExpression.cpp
+++ b/ConstantExpression.cpp
@@ -59,7 +59,6 @@
 namespace android {
 
 static inline bool isSupported(ScalarType::Kind kind) {
-    // TODO(b/64358435) move isSupported to EnumValue
     return SK(BOOL) == kind || ScalarType(kind, nullptr /* parent */).isValidEnumStorageType();
 }