Cherry-pick PR #34702 into release-3.7 (#34710)

Component commits:
7be925173c Exclude ?? operator from true/false literal check in createFlowCondition

b9802166ae Accept new API baselines

3d4c14c5f8 Add tests

7362545e8c Accept new baselines

2d1af77839 Address CR feedback

8f0de27784 Accept new API baselines

src/compiler/binder.ts

@@ -1,3 +1,4 @@
+
 /* @internal */
 namespace ts {
     export const enum ModuleInstanceState {
@@ -951,11 +952,10 @@ namespace ts {
             if (!expression) {
                 return flags & FlowFlags.TrueCondition ? antecedent : unreachableFlow;
             }
-            if (expression.kind === SyntaxKind.TrueKeyword && flags & FlowFlags.FalseCondition ||
-                expression.kind === SyntaxKind.FalseKeyword && flags & FlowFlags.TrueCondition) {
-                if (!isExpressionOfOptionalChainRoot(expression)) {
-                    return unreachableFlow;
-                }
+            if ((expression.kind === SyntaxKind.TrueKeyword && flags & FlowFlags.FalseCondition ||
+                expression.kind === SyntaxKind.FalseKeyword && flags & FlowFlags.TrueCondition) &&
+                !isExpressionOfOptionalChainRoot(expression) && !isNullishCoalesce(expression.parent)) {
+                return unreachableFlow;
             }
             if (!isNarrowingExpression(expression)) {
                 return antecedent;

src/compiler/utilities.ts

@@ -5925,6 +5925,10 @@ namespace ts {
         return isOptionalChainRoot(node.parent) && node.parent.expression === node;
     }
 
+    export function isNullishCoalesce(node: Node) {
+        return node.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>node).operatorToken.kind === SyntaxKind.QuestionQuestionToken;
+    }
+
     export function isNewExpression(node: Node): node is NewExpression {
         return node.kind === SyntaxKind.NewExpression;
     }