Implement bitwise complement operator

This translates to/from OpNot for SPIR-V, and ~ for all three textual
language backends.

Fixed: tint:866
Change-Id: Id934fb309221e3fca0e7efa33edaaae137fd8085
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/54980
Auto-Submit: James Price <jrprice@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>

src/resolver/resolver.cc

@@ -2500,6 +2500,7 @@ bool Resolver::UnaryOp(ast::UnaryOpExpression* unary) {
   const sem::Type* type = nullptr;
 
   switch (unary->op()) {
+    case ast::UnaryOp::kComplement:
     case ast::UnaryOp::kNegation:
     case ast::UnaryOp::kNot:
       // Result type matches the deref'd inner type.

src/resolver/resolver_test.cc

@@ -1946,7 +1946,8 @@ TEST_P(UnaryOpExpressionTest, Expr_UnaryOp) {
 }
 INSTANTIATE_TEST_SUITE_P(ResolverTest,
                          UnaryOpExpressionTest,
-                         testing::Values(ast::UnaryOp::kNegation,
+                         testing::Values(ast::UnaryOp::kComplement,
+                                         ast::UnaryOp::kNegation,
                                          ast::UnaryOp::kNot));
 
 TEST_F(ResolverTest, StorageClass_SetsIfMissing) {