Prevent valid JSX from being seen as the start of a generic arrow function, fix crashes (#52450)

src/compiler/parser.ts

@@ -5201,6 +5201,7 @@ namespace Parser {
                         switch (fourth) {
                             case SyntaxKind.EqualsToken:
                             case SyntaxKind.GreaterThanToken:
+                            case SyntaxKind.SlashToken:
                                 return false;
                             default:
                                 return true;

src/compiler/utilities.ts

@@ -9079,7 +9079,7 @@ export function rangeOfNode(node: Node): TextRange {
 export function rangeOfTypeParameters(sourceFile: SourceFile, typeParameters: NodeArray<TypeParameterDeclaration>): TextRange {
     // Include the `<>`
     const pos = typeParameters.pos - 1;
-    const end = skipTrivia(sourceFile.text, typeParameters.end) + 1;
+    const end = Math.min(sourceFile.text.length, skipTrivia(sourceFile.text, typeParameters.end) + 1);
     return { pos, end };
 }