[roll third_party/pigweed] pw_thread: Fix test_thread_context typo and presubmit

This CL fixes the 'text_thread_context' typo, and sets the CMake
variable `pw_thread.test_thread_context` to use `pw_thread_stl` for
`host_clang`.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/162770

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 4d6620db1bce984..62623ec50afa94e
Roller-URL: https://ci.chromium.org/b/8773762635659680065
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I7843a1594c3abfe566ce5596c135ed463b8e49a0
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/162890
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 4d6620d..62623ec 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 4d6620db1bce9847fbadf0761ee98f8e9e8edf41
+Subproject commit 62623ec50afa94e3747b436963eefc8b804a846a