[wasm] Suppress popover preview for $label identifiers.
[wasm] Suppress popover preview for $label identifiers.

Right now we don't have anything meaningful to show in the popover
preview for $label identifiers, and Debug-Evaluate in V8 will just
return `undefined` for them, which is confusing to developers. So
detect these special identifiers (operands to specific control
instructions) and suppress the popover preview for now.

Fixed: chromium:1155548
Change-Id: Ic43910dc12b535bbf572fbdde3c658b760bcb468
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3013231
Commit-Queue: Benedikt Meurer <024a1e0af501338d11c3b837c6193d11c140d792@chromium.org>
Commit-Queue: Philip Pfaffe <639a645feae3653b7aaefa0387217d375f2f82ff@chromium.org>
Auto-Submit: Benedikt Meurer <024a1e0af501338d11c3b837c6193d11c140d792@chromium.org>
Reviewed-by: Philip Pfaffe <639a645feae3653b7aaefa0387217d375f2f82ff@chromium.org>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend