[flang] Use value instead of getValue (NFC)

[kazu]

Summary

Flang C++ Style Guide tells us to use x.value() when no presence test
is obviously protecting the reference. Since a failure in EXPECT_TRUE
doesn't terminate a given test, I don't count it as "protection" here.

flang/unittests/Optimizer/Builder/FIRBuilderTest.cpp

TEST_F(FIRBuilderTest, createGlobal1) {
   auto i64Type = IntegerType::get(builder.getContext(), 64);
   auto global = builder.createGlobal(
       loc, i64Type, "global1", builder.createInternalLinkage(), {}, true);
   EXPECT_TRUE(mlir::isa<fir::GlobalOp>(global));
   EXPECT_EQ("global1", global.getSymName());
   EXPECT_TRUE(global.getConstant().has_value());
   EXPECT_EQ(i64Type, global.getType());
   EXPECT_TRUE(global.getLinkName().has_value());
-  EXPECT_EQ(builder.createInternalLinkage().getValue(),
-      global.getLinkName().getValue());
+  EXPECT_EQ(
+      builder.createInternalLinkage().getValue(), global.getLinkName().value());
   EXPECT_FALSE(global.getInitVal().has_value());
 
   auto g1 = builder.getNamedGlobal("global1");
   EXPECT_EQ(global, g1);
   auto g2 = builder.getNamedGlobal("global7");
   EXPECT_EQ(nullptr, g2);
   auto g3 = builder.getNamedGlobal("");
   EXPECT_EQ(nullptr, g3);
 }
 
 TEST_F(FIRBuilderTest, createGlobal2) {
   auto builder = getBuilder();
   auto loc = builder.getUnknownLoc();
   auto i32Type = IntegerType::get(builder.getContext(), 32);
   auto attr = builder.getIntegerAttr(i32Type, 16);
   auto global = builder.createGlobal(
       loc, i32Type, "global2", builder.createLinkOnceLinkage(), attr, false);
   EXPECT_TRUE(mlir::isa<fir::GlobalOp>(global));
   EXPECT_EQ("global2", global.getSymName());
   EXPECT_FALSE(global.getConstant().has_value());
   EXPECT_EQ(i32Type, global.getType());
   EXPECT_TRUE(global.getInitVal().has_value());
-  EXPECT_TRUE(global.getInitVal().getValue().isa<mlir::IntegerAttr>());
+  EXPECT_TRUE(global.getInitVal().value().isa<mlir::IntegerAttr>());
   EXPECT_EQ(
-      16, global.getInitVal().getValue().cast<mlir::IntegerAttr>().getValue());
+      16, global.getInitVal().value().cast<mlir::IntegerAttr>().getValue());
   EXPECT_TRUE(global.getLinkName().has_value());
-  EXPECT_EQ(builder.createLinkOnceLinkage().getValue(),
-      global.getLinkName().getValue());
+  EXPECT_EQ(
+      builder.createLinkOnceLinkage().getValue(), global.getLinkName().value());
 }
 
 TEST_F(FIRBuilderTest, uniqueCFIdent) {
   auto str1 = fir::factory::uniqueCGIdent("", "func1");
   EXPECT_EQ("_QQ.66756E6331", str1);
   str1 = fir::factory::uniqueCGIdent("", "");
   EXPECT_EQ("_QQ.", str1);
   str1 = fir::factory::uniqueCGIdent("pr", "func1");
TEST_F(FIRBuilderTest, createStringLiteral) {
   checkIntegerConstant(charBox->getLen(), builder.getCharacterLengthType(), 16);
   auto generalGetLen = fir::getLen(strLit);
   checkIntegerConstant(generalGetLen, builder.getCharacterLengthType(), 16);
   auto addr = charBox->getBuffer();
   EXPECT_TRUE(mlir::isa<fir::AddrOfOp>(addr.getDefiningOp()));
   auto addrOp = dyn_cast<fir::AddrOfOp>(addr.getDefiningOp());
   auto symbol = addrOp.getSymbol().getRootReference().getValue();
   auto global = builder.getNamedGlobal(symbol);
-  EXPECT_EQ(builder.createLinkOnceLinkage().getValue(),
-      global.getLinkName().getValue());
+  EXPECT_EQ(
+      builder.createLinkOnceLinkage().getValue(), global.getLinkName().value());
   EXPECT_EQ(fir::CharacterType::get(builder.getContext(), 1, strValue.size()),
       global.getType());
 
   auto stringLitOps = global.getRegion().front().getOps<fir::StringLitOp>();
   EXPECT_TRUE(llvm::hasSingleElement(stringLitOps));
   for (auto stringLit : stringLitOps) {
     EXPECT_EQ(16, stringLit.getSize().cast<mlir::IntegerAttr>().getValue());
     EXPECT_TRUE(stringLit.getValue().isa<StringAttr>());
     EXPECT_EQ(strValue, stringLit.getValue().dyn_cast<StringAttr>().getValue());
   }
 }
 
 TEST_F(FIRBuilderTest, allocateLocal) {
   auto builder = getBuilder();
   auto loc = builder.getUnknownLoc();
   llvm::StringRef varName = "var1";
   auto var = builder.allocateLocal(
       loc, builder.getI64Type(), "", varName, {}, {}, false);
   EXPECT_TRUE(mlir::isa<fir::AllocaOp>(var.getDefiningOp()));
   auto allocaOp = dyn_cast<fir::AllocaOp>(var.getDefiningOp());
   EXPECT_EQ(builder.getI64Type(), allocaOp.getInType());
   EXPECT_TRUE(allocaOp.getBindcName().has_value());
-  EXPECT_EQ(varName, allocaOp.getBindcName().getValue());
+  EXPECT_EQ(varName, allocaOp.getBindcName().value());
   EXPECT_FALSE(allocaOp.getUniqName().has_value());
   EXPECT_FALSE(allocaOp.getPinned());
   EXPECT_EQ(0u, allocaOp.getTypeparams().size());
   EXPECT_EQ(0u, allocaOp.getShape().size());
 }
 
 static void checkShapeOp(mlir::Value shape, mlir::Value c10, mlir::Value c100) {
   EXPECT_TRUE(mlir::isa<fir::ShapeOp>(shape.getDefiningOp()));