inspector: Re-add inspector::SamplerTexturePair

The tint -> dawn roll is failing as dawn is using tint::inspector::SamplerTexturePair.
We need to land this change, fix dawn, then revert this change.

Bug: tint:1366
Change-Id: I3a3849ddd9416a06d0be394e295603de59594ead
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/77060
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Stephen White <senorblanco@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>

src/inspector/inspector.h

diff --git a/src/inspector/inspector.h b/src/inspector/inspector.h
index e8f573f..be26eb6 100644
--- a/src/inspector/inspector.h
+++ b/src/inspector/inspector.h
@@ -32,6 +32,9 @@
 namespace tint {
 namespace inspector {
 
+/// A temporary alias to sem::SamplerTexturePair. [DEPRECATED]
+using SamplerTexturePair = sem::SamplerTexturePair;
+
 /// Extracts information from a program
 class Inspector {
  public: