Fix: Issue 10520 - [profile+nothrow] Building with profiler results in "is not nothrow" error on some contracts

When Statement#blockExit() checks if the statements may throw or not, it
can also emit compile error.
We turn the second argument of it, mustNotThrow, to false
so that the error is suppressed.
fix Issue 12970 - Enclosing @system attribute is precedence than postfix @safe
Ddoc should output qualified anchors for template members.

Fixes [issue 10366] (https://issues.dlang.org/show_bug.cgi?id=10366).
Add tests for issue 10366.
Update ddoc test outputs to have qualified anchors.
Merge pull request #3693 from quickfur/ddoc_qualified_anchors

Implement ddoc qualified anchors for template members
Merge pull request #3688 from 9rnsr/fix12970

Issue 12970 - Enclosing @system attribute is precedence than postfix @safe
fix Issue 12900 - Wrong code in IfStatement condition Expression
[WS] Replace tab with spaces.

Tab was added in d8e5f55c9b94e831b6d178a20e34144933c3fc32.
Merge pull request #3694 from denis-sh/ws-fixup-pull-3687

[Whitespace] Replace tab with spaces.
fix Issue 12967 - Prefix method 'this' qualifiers should be disallowed in DeclDefs scope
Check redundant/conflicting attributes between prefix and postfix
Fix another broken case of qualified anchors.

The previous fix didn't work for template members of templated structs.
Update ddoc test to expect fully-qualified symbols.
Fixup

Remove redundant braces.
Merge pull request #3685 from 9rnsr/fix12900

More conservative fix for issue 12900 - Wrong code in IfStatement condition Expression
Merge pull request #3689 from 9rnsr/fix12967

Issue 12967 - Prefix method 'this' qualifiers should be disallowed in DeclDefs scope
Merge pull request #3695 from quickfur/more_ddoc_anchors

DDOC fully-qualified anchors for template members of template structs/classes
Issue 10018 - Add VRP support for const/immutable variables
Merge pull request #3699 from lionello/bug10018

Issue 10018 - Add VRP support for const/immutable variables