Preserve distinction between {} and object in compiled JSON

[jeskew]

Resolves #13556

Given an object type declaration with no catchall schema, the type checker will issue warnings if a property whose name does not match any property declarations is supplied.

param example { foo: string } = { bar: 'string' }         // <-- Issues a BCP037 warning because there is no known `bar` property

@sealed()
param sealedExample { foo: string } = { bar: 'string' }   // <-- Issues a BCP037 error because there is no known `bar` property and the object is sealed

This means that given an object type declaration of {}, all supplied properties will trigger a BCP037 warning because an empty object was expected. This behaves differently from the untyped object object, which matches without warning against any object. The distinction between {} and object was getting dropped when templates were compiled to JSON, however, because the compiler wasn't including any information in the type definition that would allow the two to be distinguished; instead, they would both be compiled to {"type": "object"}.

This PR updates the compiler to include an empty properties constraint on object type declarations that include no properties so that it can tell the difference between {} and object when loading or importing from JSON modules.

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 8269011137)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 8269011137

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 8269011137"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 8269011137

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 8269011137"

[github-actions]

Test Results

    65 files   -     34      65 suites   - 34   23m 2s ⏱️ - 16m 24s
10 683 tests  -     17  10 681 ✅  -     17  2 💤 ±0  0 ❌ ±0 
25 256 runs   - 12 615  25 252 ✅  - 12 613  4 💤  - 2  0 ❌ ±0 

Results for commit 591bd06. ± Comparison against base commit 0c0394b.

♻️ This comment has been updated with latest results.

[shenglol]