cmTarget: Drop unused GetProperty signature

No callers use the second "scope" argument.  Drop this signature and
hard-code the default parameter value internally.
cmTarget: Evaluate CMP0026 and CMP0051 in calling context

These policies should be checked at the call site that tries to access
the LOCATION or SOURCES property, not the directory scope containing the
target.  Thread the caller context through cmTarget::GetProperty to use
for checking the policy setting and emitting a diagnostic with proper
backtrace.

Extend the RunCMake.CMP0026 and RunCMake.CMP0051 tests with
cross-directory cases.
Merge topic 'target-property-policy-context' into next

911cc9a3 cmTarget: Evaluate CMP0026 and CMP0051 in calling context
cb810abe cmTarget: Drop unused GetProperty signature
Test: Parameterize the language in the CompileFeature test.
Merge topic 'minor-cleanups' into next

6a9fdbeb Test: Parameterize the language in the CompileFeature test.