Handling Angle Brackets in MathML

In the following there are four pairs of math displays, corresponding to the use of four different pairs of (legitimate or not) angle bracket delimiters. In each case the first display "wants" stretching, while the second does not.

Ascii: U-003C, U-003E

First second

Miscellaneous Technical: U-2329, U-232A

First $${\int }_0^{\infty }{t}^x{e}^{-t}\frac{dt}{t}=〈\frac{1}{x}\prod _{k=1}^{\infty }\frac{{\left(1+\frac{1}{k}\right)}^x}{\left(1+\frac{x}{k}\right)}〉$$ second

Miscellaneous Mathematical A: U-27E8, U-27E9

First $${\int }_0^{\infty }{t}^x{e}^{-t}\frac{dt}{t}=⟨\frac{1}{x}\prod _{k=1}^{\infty }\frac{{\left(1+\frac{1}{k}\right)}^x}{\left(1+\frac{x}{k}\right)}⟩$$ second

CJK: U-3008, U-3009

First $${\int }_0^{\infty }{t}^x{e}^{-t}\frac{dt}{t}=〈\frac{1}{x}\prod _{k=1}^{\infty }\frac{{\left(1+\frac{1}{k}\right)}^x}{\left(1+\frac{x}{k}\right)}〉$$ second