Update Google Test from 1.10.0 to 1.15.2

[mcbarton]

The Google Test which binaryen uses is a commit sometime after version 1.10.0 looking at the readme. This PR updates the submodule to the latest release version, and pins it to the 1.15.2 release.

[mcbarton]

@kripken @sbc100 This PR is ready for review.

[sbc100]

I confirmed that b514bdc898e2951020cbdca1304b75f5950d1f59 is indeed the SHA for v1.15.2 of googletest: https://github.com/google/googletest/releases/tag/v1.15.2

[sbc100]

Out of interest @mcbarton, what sparked your recent flurry of PRs to Wasm-related repos. In particular, why did you decide that updating the version of gtest in binaryen was needed?

[mcbarton]

@sbc100 No particular reason for the flurry of PRs, or reason for the updates. Recently got into working with Web Assembly (around a few months now), and just trying to help out where I can for the tools I'm trying to make use of. Got into Web Assembly due to this project https://github.com/compiler-research/CppInterOp . At the moment I'm trying to get the latest version of GoogleTest to work with wasm to have automated wasm tests as part of the ci here (without success) compiler-research/CppInterOp#483 and thought it would be good to just double check the latest version works with regards to this PR.

[kripken]

lgtm, unless @tlively we had a reason for the specific version from before?

[tlively]

Nope, lgtm.